CN212726995U - Radio frequency signal frequency conversion processing circuit and device - Google Patents
Radio frequency signal frequency conversion processing circuit and device Download PDFInfo
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- CN212726995U CN212726995U CN202021947812.4U CN202021947812U CN212726995U CN 212726995 U CN212726995 U CN 212726995U CN 202021947812 U CN202021947812 U CN 202021947812U CN 212726995 U CN212726995 U CN 212726995U
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Abstract
The utility model relates to a radio frequency technology field discloses a radio frequency signal frequency conversion processing circuit and device. The radio frequency signal frequency conversion processing circuit comprises a pre-preselection circuit, a local oscillator circuit, a frequency conversion circuit and an intermediate frequency filtering and amplifying circuit, wherein the pre-preselection circuit acquires a radio signal, filters the radio signal to obtain a radio frequency signal and sends the radio frequency signal to the frequency conversion circuit; the local oscillation circuit provides local oscillation signals for the frequency conversion circuit; the frequency conversion circuit carries out frequency mixing on the radio frequency signal and the local oscillator signal to obtain a first intermediate frequency signal, and the level of the first intermediate frequency signal is adjusted to obtain a second intermediate frequency signal; and the intermediate frequency filtering and amplifying circuit filters and amplifies the second intermediate frequency signal and then outputs a target intermediate frequency signal. The utility model discloses carry out frequency preselection, amplification and gain control to radio signal and obtain radio frequency signal to carry out digital down conversion to target intermediate frequency signal to radio frequency signal, solved current radio frequency signal processing module incoming signal and handled the technical problem that there is quality problem in the outgoing intermediate frequency signal after.
Description
Technical Field
The utility model relates to a radio frequency technology field especially relates to a radio frequency signal frequency conversion processing circuit and device.
Background
When the frequency of the electromagnetic waves is lower, the electromagnetic waves can be absorbed by the earth surface and cannot form effective transmission, once the frequency of the electromagnetic waves is higher than a certain frequency, the electromagnetic waves can be transmitted in the air and reflected by an ionosphere at the outer edge of the atmosphere to form long-distance transmission capability, and the company refers the high-frequency electromagnetic waves with the long-distance transmission capability to radio frequency, English abbreviation: and RF. Radio frequency signals are used in many industries to transmit data, such as video calls, satellite signal positioning, aircraft radar, detection information, mobile phone GPS navigation, and the like. The radio frequency signal is a modulated electrical wave having a certain transmission frequency. In the case of television signals, to enable the transmission of television signals over the air, the video full television signal must be modulated into high Frequency or Radio Frequency (RF-Radio Frequency) signals, each occupying a channel, so that multiple television programs can be transmitted simultaneously over the air without causing confusion. The rf signal has its own characteristics, so that a special medium is required for transmitting the signal, and the corresponding connector is also special.
Radio frequency signals transmitted in the air need to be down-converted to a lower frequency, so that the signals can be conveniently and normally acquired and analyzed, but the existing radio frequency signal processing module outputs medium frequency signal harmonic waves and stray differences when inputting high-power signals, and the quality problem that the medium frequency signals are output after processing of all frequency input signals cannot be solved due to the wide working frequency range of the radio frequency signal processing module.
The above is only for the purpose of assisting understanding of the technical solutions of the present invention, and does not represent an admission that the above is the prior art.
SUMMERY OF THE UTILITY MODEL
The utility model discloses a main aim at provides a radio frequency signal frequency conversion processing circuit and device, aims at solving the technical problem that there is the quality problem in the output intermediate frequency signal after current radio frequency signal processing module input signal handles.
In order to achieve the above object, the present invention provides a radio frequency signal frequency conversion processing circuit, which comprises a pre-preselection circuit, a local oscillator circuit, a frequency conversion circuit and an intermediate frequency filtering and amplifying circuit connected in sequence; wherein the content of the first and second substances,
the pre-selection circuit is used for acquiring a radio signal received by an antenna and filtering the radio signal to obtain a radio frequency signal;
the pre-preselection circuit is also used for sending the radio frequency signal to the frequency conversion circuit through the local oscillator circuit;
the local oscillation circuit is used for providing local oscillation signals for the frequency conversion circuit;
the frequency conversion circuit is used for receiving the radio frequency signal and the local oscillator signal and mixing the radio frequency signal and the local oscillator signal to obtain a first intermediate frequency signal;
the frequency conversion circuit is also used for adjusting the level of the first intermediate frequency signal to obtain a second intermediate frequency signal;
the frequency conversion circuit is further configured to send the second intermediate-frequency signal to the intermediate-frequency filtering and amplifying circuit;
and the intermediate frequency filtering and amplifying circuit is used for outputting a target intermediate frequency signal after performing intermediate frequency filtering and amplifying on the second intermediate frequency signal.
Optionally, the pre-preselection circuit includes a limiter, a pre-amplification selector, a preselection filter, a variable attenuator, a low noise amplifier, and a low pass filter; wherein the content of the first and second substances,
the input receiving antenna of amplitude limiter received radio signal, the output of amplitude limiter with the input of preamplification selector is connected, the output of preamplification selector with the input of preselection filter is connected, preselection filter's output with variable attenuator's input is connected, variable attenuator's output with low noise amplifier's input is connected, low noise amplifier's output with low pass filter's input is connected, low pass filter's output with local oscillator circuit connects.
Optionally, the frequency conversion circuit includes: the input end of the first intermediate-frequency filtering and amplifying circuit is connected with the output end of the local oscillator circuit, the output end of the first intermediate-frequency filtering and amplifying circuit is connected with the input end of the second intermediate-frequency filtering and amplifying circuit, and the output end of the second intermediate-frequency filtering and amplifying circuit is connected with the input end of the intermediate-frequency filtering and amplifying circuit; wherein the content of the first and second substances,
the first intermediate frequency filtering and amplifying circuit is used for receiving the radio frequency signal and the local oscillator signal and mixing the radio frequency signal and the local oscillator signal to obtain a first mixing signal;
the first intermediate frequency filtering and amplifying circuit is further configured to filter out a first intermediate frequency signal according to the first mixing signal and transmit the first intermediate frequency signal to the second intermediate frequency filtering and amplifying circuit;
the second intermediate frequency filtering and amplifying circuit is used for receiving the first intermediate frequency signal and adjusting the level of the first intermediate frequency signal to obtain a second intermediate frequency signal;
and the second intermediate frequency filtering and amplifying circuit is also used for sending the second intermediate frequency signal to the intermediate frequency filtering and amplifying circuit.
Optionally, the first intermediate frequency filtering and amplifying circuit includes a first double balanced mixer and a first intermediate frequency filtering unit; wherein the content of the first and second substances,
the input end of the first double-balanced mixer is connected with the output end of the local oscillator circuit, the output end of the first double-balanced mixer is connected with the input end of the first intermediate-frequency filtering unit, and the output end of the first intermediate-frequency filtering unit is connected with the input end of the second intermediate-frequency filtering amplifying circuit.
Optionally, the second intermediate frequency filtering and amplifying circuit includes a second double balanced mixer and a second intermediate frequency filtering unit; wherein the content of the first and second substances,
the input end of the second intermediate frequency filtering unit is connected with the output end of the first intermediate frequency filtering unit, the output end of the second intermediate frequency filtering unit is connected with the input end of the second double-balanced mixer, and the output end of the second double-balanced mixer is connected with the input end of the intermediate frequency filtering amplifying circuit.
Optionally, the local oscillator circuit includes two phase-locked loop circuits; wherein the content of the first and second substances,
the phase-locked loop circuit is used for providing local oscillation signals for the frequency conversion circuit so that the frequency conversion circuit can realize sequential frequency conversion of radio frequency signals.
Optionally, the phase-locked loop circuit comprises a phase comparator, a phase-locked low-pass filter, and a voltage-controlled oscillator; wherein the content of the first and second substances,
the input of phase comparator is connected with the reference source, the output of phase comparator with the input of phase-locked low pass filter is connected, the collection end of phase comparator with voltage controlled oscillator's collection end is connected, phase-locked low pass filter's output with voltage controlled oscillator's input is connected, voltage controlled oscillator's output with frequency conversion circuit's input is connected.
Optionally, the radio signal frequency is 30MHz to 3600 MHz.
Optionally, the low noise amplifier is an integrated radio frequency low noise amplifier.
In order to achieve the above object, the present invention further provides a rf signal frequency conversion processing apparatus, which includes the rf signal frequency conversion processing circuit as described above.
The utility model provides a radio frequency signal frequency conversion processing circuit, which comprises a pre-selection circuit, a local oscillator circuit, a frequency conversion circuit and a medium frequency filter amplifying circuit which are connected in sequence; the pre-preselection circuit is used for acquiring a radio signal received by an antenna and filtering the radio signal to obtain a radio frequency signal; the pre-selection circuit is also used for sending the radio frequency signal to the frequency conversion circuit through the local oscillation circuit; the local oscillation circuit is used for providing local oscillation signals for the frequency conversion circuit; the frequency conversion circuit is used for receiving the radio frequency signal and the local oscillator signal and mixing the radio frequency signal and the local oscillator signal to obtain a first intermediate frequency signal; the frequency conversion circuit is also used for adjusting the level of the first intermediate frequency signal to obtain a second intermediate frequency signal; the frequency conversion circuit is also used for sending the second intermediate frequency signal to the intermediate frequency filtering and amplifying circuit; and the intermediate frequency filtering and amplifying circuit is used for outputting a target intermediate frequency signal after performing intermediate frequency filtering and amplifying on the second intermediate frequency signal. The utility model discloses in, radio frequency signal frequency conversion processing circuit realizes frequency preselection, amplification and gain control to whole receiving frequency channel, guarantees to have higher sensitivity and great dynamic range, realizes sampling from the radio frequency signal to carry out the conversion process of digital down-conversion to target intermediate frequency signal to the radio frequency signal, promoted signal acquisition's precision and purity, solved the technical problem that there is quality problem in the output intermediate frequency signal after current radio frequency signal processing module input signal handles.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
Fig. 1 is a functional block diagram of an embodiment of the rf signal frequency conversion processing circuit of the present invention;
fig. 2 is a schematic circuit diagram of an embodiment of the rf signal frequency conversion processing circuit of the present invention;
fig. 3 is a schematic structural diagram of a pre-selection circuit according to an embodiment of the rf signal frequency conversion processing circuit of the present invention;
fig. 4 is a schematic diagram of a phase-locked loop circuit structure according to an embodiment of the rf signal frequency conversion processing circuit of the present invention;
fig. 5 is a schematic diagram of a signal processing flow of an embodiment of the rf signal frequency conversion processing circuit of the present invention;
fig. 6 is a schematic diagram of a general frequency hopping processing flow according to an embodiment of the rf signal frequency conversion processing circuit of the present invention;
fig. 7 is a schematic diagram illustrating an unknown signal detection and identification process according to an embodiment of the rf signal frequency conversion processing circuit of the present invention.
The reference numbers illustrate:
| reference numerals | Name (R) | Reference numerals | Name (R) |
| 100 | Pre-pre- |
301 | First intermediate frequency filtering and amplifying |
| 200 | |
302 | Second intermediate frequency filtering amplifying |
| 300 | |
3011 | First double balanced |
| 400 | Intermediate frequency filtering amplifying |
3012 | First intermediate |
| 101 | |
3021 | Second double |
| 102 | Pre-amplification |
3022 | Second intermediate |
| 103 | |
201 | Phase-locked |
| 104 | |
2011 | |
| 105 | |
2012 | Phase-locked low- |
| 106 | Low- |
2013 | Voltage controlled oscillator |
The objects, features and advantages of the present invention will be further described with reference to the accompanying drawings.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
It should be noted that all the directional indicators (such as upper, lower, left, right, front and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicator is changed accordingly.
In addition, the descriptions related to "first", "second", etc. in the present invention are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit ly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should not be considered to exist, and is not within the protection scope of the present invention.
The utility model provides a radio frequency signal frequency conversion processing circuit.
Referring to fig. 1, in the embodiment of the present invention, the radio frequency signal frequency conversion processing circuit includes a pre-preselection circuit 100, a local oscillator circuit 200, a frequency conversion circuit 300, and an intermediate frequency filtering and amplifying circuit 400, which are connected in sequence; wherein the content of the first and second substances,
the pre-preselection circuit 100 is configured to acquire a radio signal received by an antenna, and filter the radio signal to obtain a radio frequency signal. In this embodiment, the radio signal received from the antenna may be transmitted to the preselection circuit 100 via the radio frequency cable, and the preselection circuit 100 may be composed of an amplitude limiter, a pre-amplification selector, a preselection filter, a variable attenuator, a low noise amplifier, a low pass filter, and the like; the preselection filter fully considers the radio frequency signals which are weak in signals and easy to submerge in noise in the radio signals, the low-noise amplifier can be an integrated radio frequency low-noise amplifier which is wide in dynamic range, low in noise coefficient and moderate in gain, frequency preselection, amplification and gain control of the input radio signals are achieved, high sensitivity and large dynamic range are guaranteed, and therefore the radio signals are filtered through the pre-preselection circuit 100 to obtain the radio frequency signals.
The pre-selection circuit 100 is further configured to send the radio frequency signal to the frequency conversion circuit 300 through the local oscillation circuit 200. In this embodiment, the pre-selection circuit 100 sends the radio frequency signal to the frequency conversion circuit 300 through the local oscillator circuit 200, so that the frequency conversion circuit 300 performs frequency mixing according to the radio frequency signal and the local oscillator signal.
The local oscillation circuit 200 is configured to provide a local oscillation signal for the frequency conversion circuit 300. In this embodiment, the local oscillator circuit 200 may include two phase-locked loop circuits 201, where the phase-locked loop circuits 201 provide local oscillator signals for the frequency conversion circuit 300, and the local oscillator signals include suitable working frequency points and local oscillator power, so that the frequency conversion circuit 300 realizes sequential frequency conversion of radio frequency signals. The phase-locked loop circuit 201 has the characteristics of low phase noise, less stray signals, less combined interference and the like.
The frequency conversion circuit 300 is configured to receive the radio frequency signal and the local oscillator signal, and perform frequency mixing on the radio frequency signal and the local oscillator signal to obtain a first intermediate frequency signal. In this embodiment, the frequency conversion circuit 300 sequentially performs frequency conversion on the radio frequency signal twice according to the local oscillation signal, and outputs a target intermediate frequency signal so as to perform AD processing. The frequency conversion circuit 300 may include a first if filter and amplifier circuit and a second if filter and amplifier circuit; the first intermediate frequency filtering and amplifying circuit receives a radio frequency signal and a local oscillator signal, and mixes the radio frequency signal and the local oscillator signal to obtain a first mixing signal; the first intermediate frequency filtering amplifying circuit filters out a first intermediate frequency signal according to the first mixing signal and transmits the first intermediate frequency signal to the second intermediate frequency filtering amplifying circuit.
The frequency conversion circuit 300 is further configured to adjust a level of the first intermediate frequency signal to obtain a second intermediate frequency signal. In this embodiment, the frequency conversion circuit 300 may include a first intermediate frequency filtering and amplifying circuit and a second intermediate frequency filtering and amplifying circuit; the second intermediate frequency filtering and amplifying circuit receives the first intermediate frequency signal and adjusts the level of the first intermediate frequency signal to obtain a second intermediate frequency signal; the second if filter amplifier circuit transmits the second if signal to the if filter amplifier circuit 400.
The frequency conversion circuit 300 is further configured to send the second intermediate frequency signal to the intermediate frequency filtering and amplifying circuit 400.
The intermediate frequency filtering and amplifying circuit 400 is configured to perform intermediate frequency filtering and amplifying on the second intermediate frequency signal, and then output a target intermediate frequency signal. In the embodiment, the radio signals of 30MHz to 3600MHz are collected, the target intermediate frequency signals with moderate frequency are formed after frequency conversion processing, and the target intermediate frequency signals can be limited in a proper bandwidth through the radio frequency signal frequency conversion processing circuit, so that the target intermediate frequency signals after analog-to-digital conversion cannot be subjected to aliasing. Because the gain of the radio frequency receiving and frequency conversion channel cannot be too high, the level of the target intermediate frequency signal output by multiple frequency mixing is low, so that the effective number of bits obtained by the target intermediate frequency signal after analog-to-digital conversion is less, and the digitization performance is affected. Through the variable gain control of the intermediate frequency adjustment, the level of the first intermediate frequency signal can be adjusted to the second intermediate frequency signal of the optimal quantization level, and after the level adjustment and the intermediate frequency filtering amplification circuit 400 performs the intermediate frequency filtering amplification, the finally obtained target intermediate frequency signal is input to the analog-to-digital conversion unit for the analog-to-digital conversion processing.
It should be noted that the input end and the output end of the preselection circuit 100, the local oscillator circuit 200, and the intermediate frequency filtering and amplifying circuit 400 include a Single Pole multiple Throw (SP 4T) (not shown), and the radio frequency signal frequency conversion processing circuit may also adopt other types of switches according to actual needs, which is not limited in this embodiment.
In this embodiment, the radio frequency signal frequency conversion processing circuit includes a pre-preselection circuit 100, a local oscillator circuit 200, a frequency conversion circuit 300, and an intermediate frequency filtering and amplifying circuit 400, which are connected in sequence; the pre-preselection circuit 100 is configured to acquire a radio signal received by an antenna, and filter the radio signal to obtain a radio frequency signal; the pre-preselection circuit 100 is further configured to send the radio frequency signal to the frequency conversion circuit 300 through the local oscillator circuit 200; the local oscillation circuit 200 is configured to provide a local oscillation signal for the frequency conversion circuit 300; the frequency conversion circuit 300 is configured to receive the radio frequency signal and the local oscillator signal, and perform frequency mixing on the radio frequency signal and the local oscillator signal to obtain a first intermediate frequency signal; the frequency conversion circuit 300 is further configured to adjust a level of the first intermediate frequency signal to obtain a second intermediate frequency signal; the frequency conversion circuit 300 is further configured to send the second intermediate frequency signal to the intermediate frequency filtering and amplifying circuit 400; the intermediate frequency filtering and amplifying circuit 400 is configured to perform intermediate frequency filtering and amplifying on the second intermediate frequency signal, and then output a target intermediate frequency signal. In the embodiment, the radio frequency signal frequency conversion processing circuit realizes frequency preselection, amplification and gain control of the whole receiving frequency band, ensures higher sensitivity and larger dynamic range, realizes sampling from the radio frequency signal, and performs a conversion process from digital down conversion to a target intermediate frequency signal on the radio frequency signal, improves the precision and purity of signal acquisition, and solves the technical problem that the quality problem exists in the output intermediate frequency signal after the input signal of the existing radio frequency signal processing module is processed.
Further, referring to fig. 2 and 3, the preselection pre-circuit 100 includes a limiter 101, a pre-amplification selector 102, a preselection filter 103, a variable attenuator 104, a low noise amplifier 105, and a low pass filter 106; wherein the content of the first and second substances,
the input end of the limiter 101 receives a radio signal received by an antenna, the output end of the limiter 101 is connected with the input end of the pre-amplification selector 102, the output end of the pre-amplification selector 102 is connected with the input end of the pre-selection filter 103, the output end of the pre-selection filter 103 is connected with the input end of the variable attenuator 104, the output end of the variable attenuator 104 is connected with the input end of the low noise amplifier 105, the output end of the low noise amplifier 105 is connected with the input end of the low pass filter 106, and the output end of the low pass filter 106 is connected with the local oscillator circuit 200.
It should be noted that, the preselection filter 103 fully considers the radio frequency signals that are weak signals in the radio signals and are easily submerged in noise, and the low noise amplifier 105 may select an integrated radio frequency low noise amplifier with a wide dynamic range, a low noise coefficient, and a moderate gain, to implement frequency preselection, amplification, and gain control of the input radio signals, and ensure a high sensitivity and a large dynamic range, so as to filter the radio signals through the preselection circuit 100, thereby obtaining the radio frequency signals.
It is easy to understand that the limiter is used for protecting the signal input terminal of the preselection circuit 100, so as to prevent the radio frequency signal frequency conversion processing circuit from being damaged when the input radio signal is a strong signal. When the overall input level of the radio signal is small and the target signal is very weak, a better receiving sensitivity (low noise mode) can be obtained by using the low noise amplifier 105 of the preselection circuit 100, and the low noise amplifier 105 has the characteristics of small noise coefficient, good amplitude-frequency response, high saturation level and the like.
Further, referring to fig. 2, the frequency conversion circuit 300 includes: a first intermediate frequency filtering and amplifying circuit 301 and a second intermediate frequency filtering and amplifying circuit 302, wherein an input end of the first intermediate frequency filtering and amplifying circuit 301 is connected with an output end of the local oscillator circuit 200, an output end of the first intermediate frequency filtering and amplifying circuit 301 is connected with an input end of the second intermediate frequency filtering and amplifying circuit 302, and an output end of the second intermediate frequency filtering and amplifying circuit 302 is connected with an input end of the intermediate frequency filtering and amplifying circuit 400; wherein the content of the first and second substances,
the first intermediate frequency filtering and amplifying circuit 301 is configured to receive the radio frequency signal and the local oscillator signal, and mix the radio frequency signal and the local oscillator signal to obtain a first mixed frequency signal;
the first intermediate frequency filtering and amplifying circuit 301 is further configured to filter out a first intermediate frequency signal according to the first mixing signal, and transmit the first intermediate frequency signal to the second intermediate frequency filtering and amplifying circuit 302;
the second intermediate frequency filtering and amplifying circuit 302 is configured to receive the first intermediate frequency signal, and adjust a level of the first intermediate frequency signal to obtain a second intermediate frequency signal;
the second intermediate frequency filtering and amplifying circuit 302 is further configured to send the second intermediate frequency signal to the intermediate frequency filtering and amplifying circuit 400.
It should be noted that the frequency conversion circuit 300 may include a first if filter amplifier circuit 301 and a second if filter amplifier circuit 302; the frequency conversion circuit 300 sequentially performs frequency conversion on the radio frequency signal twice according to the local oscillator signal through the first intermediate frequency filtering and amplifying circuit 301 and the second intermediate frequency filtering and amplifying circuit 302, and outputs a target intermediate frequency signal so as to perform digital-to-analog conversion processing.
Specifically, the first intermediate frequency filtering and amplifying circuit 301 receives a radio frequency signal and a local oscillator signal, and mixes the radio frequency signal and the local oscillator signal to obtain a first mixed frequency signal; the first if filter amplifier circuit 301 filters out the first if signal according to the first mixing signal, and transmits the first if signal to the second if filter amplifier circuit 302. The first if filtering and amplifying circuit 301 may filter out the first if signal through a two-level high out-of-band rejection band-pass filter, and filter out other spurious signals (e.g., local oscillator leakage signal, inter-modulation interference signal after frequency mixing, etc.), and the first if filtering and amplifying circuit 301 may further include an amplifier for adjusting the first if signal to compensate for a level of the first if signal that is reduced due to frequency conversion loss, link loss, etc.
Specifically, the second intermediate frequency filtering and amplifying circuit 302 receives the first intermediate frequency signal and adjusts the level of the first intermediate frequency signal to obtain a second intermediate frequency signal; the second intermediate frequency filtering and amplifying circuit 302 transmits the second intermediate frequency signal to the intermediate frequency filtering and amplifying circuit 400. The target intermediate frequency signal can be limited within a suitable bandwidth by the second intermediate frequency filtering and amplifying circuit 302, so that the target intermediate frequency signal after analog-to-digital conversion does not generate aliasing. Because the gain of the radio frequency receiving and frequency conversion channel cannot be too high, the level of the target intermediate frequency signal output by multiple frequency mixing is low, so that the effective number of bits obtained by the target intermediate frequency signal after analog-to-digital conversion is less, and the digitization performance is affected. Through the variable gain control of the intermediate frequency adjustment, the second intermediate frequency filtering and amplifying circuit 302 may adjust the level of the first intermediate frequency signal to the second intermediate frequency signal of the optimal quantization level, and after the level adjustment and intermediate frequency filtering and amplifying circuit 400 performs the intermediate frequency filtering and amplifying, the finally obtained target intermediate frequency signal is input to the analog-to-digital conversion unit for the analog-to-digital conversion processing.
Further, referring to fig. 2, the first if filtering and amplifying circuit 301 includes a first double balanced mixer 3011 and a first if filtering unit 3012; wherein the content of the first and second substances,
an input end of the first double-balanced mixer 3011 is connected to an output end of the local oscillator circuit 200, an output end of the first double-balanced mixer 3011 is connected to an input end of the first intermediate-frequency filtering unit 3012, and an output end of the first intermediate-frequency filtering unit 3012 is connected to an input end of the second intermediate-frequency filtering and amplifying circuit 302.
It should be noted that the first if filtering and amplifying circuit 301 may include a first double-balanced mixer 3011 and a first if filtering unit 3012, where the first if filtering unit 3012 may filter out the first if signal through a two-level high-out-of-band rejection band-pass filter and filter out other spurious signals (such as local oscillator leakage signals and intermodulation interference signals after mixing), and the first if filtering unit 3012 may further include an amplifier for adjusting the first if signal to compensate for a level of the first if signal that is reduced due to frequency conversion loss and link loss. The first intermediate frequency filtering and amplifying circuit 301 may select a double balanced mixer with high saturation level, high isolation, and low frequency conversion loss, which has low combined interference, as the first double balanced mixer 3011, effectively reduce combined interference, suppress intermediate frequency, local oscillation frequency, image frequency, and the like, and improve the dynamic range of received signals.
Further, referring to fig. 2, the second intermediate frequency filtering and amplifying circuit 302 includes a second double balanced mixer 3021 and a second intermediate frequency filtering unit 3022; wherein the content of the first and second substances,
an input terminal of the second intermediate frequency filtering unit 3022 is connected to an output terminal of the first intermediate frequency filtering unit 3012, an output terminal of the second intermediate frequency filtering unit 3022 is connected to an input terminal of the second double balanced mixer 3021, and an output terminal of the second double balanced mixer 3021 is connected to an input terminal of the intermediate frequency filtering and amplifying circuit 400.
It should be noted that the second if filtering and amplifying circuit 302 is mainly used for filtering out if signals with different bandwidths and adjusting the level of the if signals. Outputting a second intermediate frequency signal obtained after the second frequency mixing to the intermediate frequency filtering and amplifying circuit 400, and performing low-pass filtering, adjustable attenuation, gain amplification and selective filtering on the second intermediate frequency signal by the intermediate frequency filtering and amplifying circuit 400 to realize gain control, clutter suppression, output matching and the like on the second intermediate frequency signal; intermediate frequency signals of different bandwidths can be selected by the intermediate frequency filter bank in the intermediate frequency filtering and amplifying circuit 400.
Specifically, the frequency range RFIN of the input radio signal may be 30MHz to 3600MHz, the frequency range LO1 of the first if filter amplifier circuit 301 may be 1950 to 3150MHz, and the frequency range LO2 of the second if filter amplifier circuit 302 may be 1150 to 1155MHz, so that the target if signal frequency output by the rf signal frequency conversion processing module may be 150MHz according to LO2- (LO1-RFIN), and the bandwidth of the output target if signal may be 50MHz through the filter in the if filter amplifier circuit 400.
Further, referring to fig. 2, the local oscillator circuit 200 includes two phase-locked loop circuits 201; wherein the content of the first and second substances,
the phase-locked loop circuit 201 is configured to provide the local oscillator signal for the frequency conversion circuit 300, so that the frequency conversion circuit 300 realizes sequential frequency conversion of the radio frequency signal.
It should be noted that the local oscillator circuit 200 may include two phase-locked loop circuits 201, where the phase-locked loop circuits 201 provide local oscillator signals for the frequency conversion circuit 300, and the local oscillator signals include suitable working frequency points and local oscillator power, so that the frequency conversion circuit 300 realizes sequential frequency conversion of radio frequency signals. The phase-locked loop circuit 201 has the characteristics of low phase noise, less stray signals, less combined interference and the like.
Further, referring to fig. 2 and 4, the phase-locked loop circuit 201 includes a phase comparator 2011, a phase-locked low-pass filter 2012, and a voltage-controlled oscillator 2013; wherein the content of the first and second substances,
the input of phase comparator 2011 is connected with the reference source, the output of phase comparator 2011 with the input of phase-locked low pass filter 2012 is connected, the collection end of phase comparator 2011 with the collection end of voltage controlled oscillator 2013 is connected, the output of phase-locked low pass filter 2012 with the input of voltage controlled oscillator 2013 is connected, the output of voltage controlled oscillator 2013 with frequency conversion circuit 300's input is connected.
It should be noted that the pll circuit 201 includes a phase comparator 2011, a phase-locked low-pass filter 2012 and a voltage-controlled oscillator 2013, the phase comparator 2011 is located at the center of the pll circuit 201, the phase comparator 2011 can compare the phase of the reference signal input by the reference source with the phase of the voltage-controlled oscillator 2013, and if there is a phase difference between the two signals, the pll circuit 201 generates a phase error signal to output.
Specifically, the phase comparator 2011 in the pll circuit 201 is also called a phase detector, and is configured to detect a phase difference between an input signal and an output signal, convert the detected phase difference signal into a ud (t) voltage signal, output the ud (t) voltage signal, filter the ud (t) voltage signal by the phase-locked low-pass filter 2012, form a control voltage uc (t) of the vco 2013, and control the frequency of the output local oscillation signal.
Further, the radio signal frequency is 30MHz to 3600 MHz.
It should be noted that, in the present embodiment, the rf signal frequency conversion processing module has 2 channels for simultaneously collecting and inputting, the frequency range of the input radio signal may be 30MHz to 3600MHz, and the power of the input radio signal may be-80 dBm to-10 dBm. The frequency of a target intermediate frequency signal output by the radio frequency signal frequency conversion processing module can be 150MHz, the bandwidth of the output target intermediate frequency signal can be 50MHz, the radio frequency signal frequency conversion processing module has a wider gain control range, wherein the gain adjustment step can be 1dB, the frequency step can be 1KHz, and the radio frequency signal frequency conversion processing module has good intermediate frequency suppression and image frequency suppression performances.
It is easy to understand that, in this embodiment, the radio frequency signal frequency conversion processing module may acquire a radio frequency signal of 30MHz to 3600MHz, and may also acquire other frequency band signals, and the radio frequency signal frequency conversion processing module may not only realize intermediate frequency processing of multiple frequencies, but also realize multiple signal bandwidths, and only needs to change and adjust relevant parameters inside the radio frequency signal frequency conversion processing module, which is not limited in this embodiment.
Further, the low noise amplifier 105 is an integrated radio frequency low noise amplifier.
It should be noted that the low noise amplifier 105 may be an integrated radio frequency low noise amplifier, and the low noise amplifier 105 is an integrated radio frequency low noise amplifier with a wide dynamic range, a low noise coefficient, and a moderate gain, so as to implement frequency preselection, amplification, and gain control of an input radio signal, and ensure a high sensitivity and a large dynamic range.
It is easy to understand that, based on the above radio frequency signal frequency conversion processing circuit, several processing modes can be developed in software, wherein the processing mode of software design may include: signal processing flow, general frequency hopping processing flow, unknown signal detection and identification flow and the like. Referring to fig. 5, fig. 5 is a schematic diagram of a signal processing flow of an embodiment of the rf signal frequency conversion processing circuit of the present invention; referring to fig. 6, fig. 6 is a schematic diagram of a general frequency hopping processing flow according to an embodiment of the radio frequency signal frequency conversion processing circuit of the present invention; referring to fig. 7, fig. 7 is a schematic diagram illustrating an unknown signal detection and identification process according to an embodiment of the rf signal frequency conversion processing circuit of the present invention; the processing modes of the radio frequency signal frequency conversion processing circuit hardware and the software design are combined with each other, and the radio frequency signal frequency conversion processing circuit has strong signal acquisition and signal processing capabilities and excellent parameter performance by matching the radio frequency signal frequency conversion processing circuit hardware and the software design.
In order to achieve the above object, the present invention further provides a rf signal frequency conversion processing apparatus, which comprises the rf signal frequency conversion processing circuit. The specific structure of the rf signal frequency conversion processing circuit refers to the above embodiments, and since the rf signal frequency conversion processing apparatus adopts all the technical solutions of all the above embodiments, at least all the beneficial effects brought by the technical solutions of the above embodiments are achieved, and are not described in detail herein.
The above only is the preferred embodiment of the present invention, not limiting the scope of the present invention, all the equivalent structure changes made by the contents of the specification and the drawings under the inventive concept of the present invention, or the direct/indirect application in other related technical fields are included in the patent protection scope of the present invention.
Claims (10)
1. A radio frequency signal frequency conversion processing circuit is characterized by comprising a pre-preselection circuit, a local oscillator circuit, a frequency conversion circuit and an intermediate frequency filtering and amplifying circuit which are sequentially connected; wherein the content of the first and second substances,
the pre-selection circuit is used for acquiring a radio signal received by an antenna and filtering the radio signal to obtain a radio frequency signal;
the pre-preselection circuit is also used for sending the radio frequency signal to the frequency conversion circuit through the local oscillator circuit;
the local oscillation circuit is used for providing local oscillation signals for the frequency conversion circuit;
the frequency conversion circuit is used for receiving the radio frequency signal and the local oscillator signal and mixing the radio frequency signal and the local oscillator signal to obtain a first intermediate frequency signal;
the frequency conversion circuit is also used for adjusting the level of the first intermediate frequency signal to obtain a second intermediate frequency signal;
the frequency conversion circuit is further configured to send the second intermediate-frequency signal to the intermediate-frequency filtering and amplifying circuit;
and the intermediate frequency filtering and amplifying circuit is used for outputting a target intermediate frequency signal after performing intermediate frequency filtering and amplifying on the second intermediate frequency signal.
2. The rf signal processing circuit of claim 1, wherein the preselection pre-stage circuit includes a limiter, a pre-amplification selector, a preselection filter, a variable attenuator, a low noise amplifier, and a low pass filter; wherein the content of the first and second substances,
the input receiving antenna of amplitude limiter received radio signal, the output of amplitude limiter with the input of preamplification selector is connected, the output of preamplification selector with the input of preselection filter is connected, preselection filter's output with variable attenuator's input is connected, variable attenuator's output with low noise amplifier's input is connected, low noise amplifier's output with low pass filter's input is connected, low pass filter's output with local oscillator circuit connects.
3. The radio frequency signal frequency conversion processing circuit according to claim 1, wherein the frequency conversion circuit includes: the input end of the first intermediate-frequency filtering and amplifying circuit is connected with the output end of the local oscillator circuit, the output end of the first intermediate-frequency filtering and amplifying circuit is connected with the input end of the second intermediate-frequency filtering and amplifying circuit, and the output end of the second intermediate-frequency filtering and amplifying circuit is connected with the input end of the intermediate-frequency filtering and amplifying circuit; wherein the content of the first and second substances,
the first intermediate frequency filtering and amplifying circuit is used for receiving the radio frequency signal and the local oscillator signal and mixing the radio frequency signal and the local oscillator signal to obtain a first mixing signal;
the first intermediate frequency filtering and amplifying circuit is further configured to filter out a first intermediate frequency signal according to the first mixing signal and transmit the first intermediate frequency signal to the second intermediate frequency filtering and amplifying circuit;
the second intermediate frequency filtering and amplifying circuit is used for receiving the first intermediate frequency signal and adjusting the level of the first intermediate frequency signal to obtain a second intermediate frequency signal;
and the second intermediate frequency filtering and amplifying circuit is also used for sending the second intermediate frequency signal to the intermediate frequency filtering and amplifying circuit.
4. The rf signal processing circuit of claim 3, wherein the first if filter amplifying circuit includes a first double balanced mixer and a first if filter unit; wherein the content of the first and second substances,
the input end of the first double-balanced mixer is connected with the output end of the local oscillator circuit, the output end of the first double-balanced mixer is connected with the input end of the first intermediate-frequency filtering unit, and the output end of the first intermediate-frequency filtering unit is connected with the input end of the second intermediate-frequency filtering amplifying circuit.
5. The radio frequency signal frequency conversion processing circuit according to claim 4, wherein the second IF filtering amplifying circuit includes a second double balanced mixer and a second IF filtering unit; wherein the content of the first and second substances,
the input end of the second intermediate frequency filtering unit is connected with the output end of the first intermediate frequency filtering unit, the output end of the second intermediate frequency filtering unit is connected with the input end of the second double-balanced mixer, and the output end of the second double-balanced mixer is connected with the input end of the intermediate frequency filtering amplifying circuit.
6. The radio frequency signal frequency conversion processing circuit according to claim 1, wherein the local oscillator circuit includes two phase-locked loop circuits; wherein the content of the first and second substances,
the phase-locked loop circuit is used for providing local oscillation signals for the frequency conversion circuit so that the frequency conversion circuit can realize sequential frequency conversion of radio frequency signals.
7. The radio frequency signal frequency conversion processing circuit according to claim 6, wherein the phase-locked loop circuit includes a phase comparator, a phase-locked low-pass filter, and a voltage-controlled oscillator; wherein the content of the first and second substances,
the input of phase comparator is connected with the reference source, the output of phase comparator with the input of phase-locked low pass filter is connected, the collection end of phase comparator with voltage controlled oscillator's collection end is connected, phase-locked low pass filter's output with voltage controlled oscillator's input is connected, voltage controlled oscillator's output with frequency conversion circuit's input is connected.
8. The RF signal processing circuit according to any of claims 1 to 7, wherein the RF signal frequency is in a range of 30MHz to 3600 MHz.
9. The radio frequency signal frequency conversion processing circuit of claim 2, wherein the low noise amplifier is an integrated radio frequency low noise amplifier.
10. A radio frequency signal frequency conversion processing device, characterized in that the radio frequency signal frequency conversion processing device comprises the radio frequency signal frequency conversion processing circuit according to any one of claims 1 to 9.
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| CN202021947812.4U CN212726995U (en) | 2020-09-08 | 2020-09-08 | Radio frequency signal frequency conversion processing circuit and device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113300674A (en) * | 2021-05-12 | 2021-08-24 | 上海明波通信技术股份有限公司 | Local oscillator leakage suppression circuit and direct up-conversion transmitter |
| CN116707573A (en) * | 2023-05-24 | 2023-09-05 | 苏州莱尔微波技术有限公司 | Variable frequency channel assembly |
-
2020
- 2020-09-08 CN CN202021947812.4U patent/CN212726995U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113300674A (en) * | 2021-05-12 | 2021-08-24 | 上海明波通信技术股份有限公司 | Local oscillator leakage suppression circuit and direct up-conversion transmitter |
| CN113300674B (en) * | 2021-05-12 | 2023-08-22 | 深圳市深精电科技有限公司 | Local oscillator leakage suppression circuit and direct up-conversion transmitter |
| CN116707573A (en) * | 2023-05-24 | 2023-09-05 | 苏州莱尔微波技术有限公司 | Variable frequency channel assembly |
| CN116707573B (en) * | 2023-05-24 | 2024-01-26 | 苏州莱尔微波技术有限公司 | Variable frequency channel assembly |
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