CN210041809U

CN210041809U - Novel preceding stage circuit for improving dynamic range of receiving system

Info

Publication number: CN210041809U
Application number: CN201921493315.9U
Authority: CN
Inventors: 李成锋
Original assignee: Wuxi Huace Electronic System Co Ltd
Current assignee: Wuxi Huace Electronic System Co Ltd
Priority date: 2019-09-09
Filing date: 2019-09-09
Publication date: 2020-02-07
Anticipated expiration: 2029-09-09

Abstract

The utility model discloses an improve receiving system dynamic range's novel preceding stage circuit, relate to microwave communication technical field, this novel preceding stage circuit simple structure, only increase one-level numerical control decay circuit in conventional preceding stage circuit, utilize power detection circuit and controller among the conventional circuit structure to realize the control to numerical control decay circuit according to received signal's power, adopt the 0 attitude and the decay attitude of numerical control decay circuit to carry out the mode of switching, can improve and receive input 1dB compression point, thereby improve and receive dynamic range, especially when receiving system requires input 1dB compression point to be higher than-5 dBm, can reach the system requirement easily, can also reduce receiving system preceding stage amplifier's the design lectotype degree of difficulty, numerical control attenuator technique is more mature simultaneously, circuit application frequency range broad, the commonality is better.

Description

Novel preceding stage circuit for improving dynamic range of receiving system

Technical Field

The utility model belongs to the technical field of the microwave communication technique and specifically relates to an improve receiving system dynamic range's novel preceding stage circuit.

Background

The dynamic range of the receiving system is an important index for measuring the performance of the receiving system, the dynamic range refers to the power amplitude range of the input signal which can be detected by the receiving system and can ensure that the received signal is not distorted, the minimum detectable power is the sensitivity Smin, and the maximum undistorted power is the compression point of the received input 1 dB. Wherein, according to the sensitivity formula, Smin ═ 114+10log (BW) + NF, BW is the receiving system bandwidth, NF is the receiving noise figure, so under the condition that the receiving system bandwidth BW is fixed, the sensitivity Smin directly depends on the system noise figure, i.e. the system dynamic range mainly depends on the receiving input 1dB compression point and the noise figure.

According to the current technical level, the performance of the preamplifier of the receiving system is the key for limiting the dynamic range of the whole system, when the dynamic range required by the system is large, particularly when the compression point of input 1dB required by the receiving system is higher than-5 dBm, the difficulty of model selection design of the preamplifier is very high, and the model selection design is usually difficult to realize in practical operation.

SUMMERY OF THE UTILITY MODEL

The inventor of the present invention has proposed a novel preceding stage circuit for improving dynamic range of a receiving system aiming at the above problems and technical requirements, the technical scheme of the utility model is as follows:

a new kind of pre-stage circuits to improve the dynamic range of the receiving system, this new pre-stage circuit includes several stages of pre-stage amplifiers connected in series sequentially, the input end of the serial circuit formed is regarded as the input end of the new pre-stage circuit and obtains the received signal, the output end of the serial circuit is regarded as the output end of the new pre-stage circuit and connected with the post-stage circuit of the receiving system, the serial circuit has numerical control decay circuit among several stages of pre-stage amplifiers still connected in series; the input end of the power detection circuit is connected with the input end of the novel pre-stage circuit, the output end of the power detection circuit is connected with the controller, the controller is connected with and controls the control end of the numerical control attenuation circuit, and the numerical control attenuation circuit is in a 0 state and provides a 0dB attenuation value or is in an attenuation state and provides a preset attenuation value under the action of a signal of the control end.

The further technical scheme is that the numerical control attenuation circuit is realized by adopting a 1-bit digital positive control attenuator chip, a radio-frequency signal input end and a radio-frequency signal output end of the 1-bit digital positive control attenuator chip are respectively connected with two adjacent stages of pre-amplifiers, and a control end of the 1-bit digital positive control attenuator chip is connected with a controller.

The utility model has the beneficial technical effects that:

the application discloses improve novel preceding stage circuit of receiving system dynamic range, this novel preceding stage circuit simple structure, only increase one-level numerical control decay circuit in conventional preceding stage circuit, utilize power detection circuit and controller among the conventional preceding stage circuit to realize the control to numerical control decay circuit according to received signal's power, adopt the mode that 0 attitude and the decay attitude of numerical control decay circuit switched, can improve the 1dB compression point of receiving input, thereby improve and receive dynamic range, especially when receiving system requires that input 1dB compression point is higher than-5 dBm, can reach the system requirement easily, can also reduce the design lectotype degree of difficulty of receiving system preceding stage amplifier, numerical control attenuator technique is more mature simultaneously, the circuit is suitable for the frequency channel broad, the commonality is better.

Drawings

Fig. 1 is a schematic circuit diagram of a novel front stage circuit disclosed in the present application.

Fig. 2 is an architecture diagram of a chip used in one example of the digitally controlled attenuation circuit of the present application.

Detailed Description

The following describes the embodiments of the present invention with reference to the accompanying drawings.

The application discloses improve novel preceding stage circuit of receiving system dynamic range please refer to fig. 1, this novel preceding stage circuit includes a plurality of grades of preamplifier that establish ties in proper order, and the serial circuit that preceding stage amplifier formed still establishes ties between a plurality of grades of preamplifier and has numerical control decay circuit, and fig. 1 uses first-order amplifier V1 and second-order amplifier V2 to form the serial circuit and establish ties numerical control decay circuit between first-order amplifier V1 and second-order amplifier V2 as an example. The input of the formed series circuit is used as the input of the novel preceding stage circuit to obtain a receiving signal, the output of the formed series circuit is used as the output of the novel preceding stage circuit to be connected with a receiving system rear stage circuit, the input of the power detection circuit is connected with the input of the novel preceding stage circuit, the output of the power detection circuit is connected with the controller, and the controller is connected with and controls the control end of the numerical control attenuation circuit. The power detection circuit is a conventional circuit, and in the current receiving system, the power detection circuit is limited by conditions such as gain of an amplifier, an input 1dB compression point, a noise coefficient and the like, and in order to ensure that a large signal cannot cause distortion of devices at each stage in the circuit, the power of the received signal must be detected and the gain of the received signal must be controlled according to a detection result, so that the power detection circuit is also a circuit generally existing in the current receiving system, and the specific circuit structure of the power detection circuit is not described in detail in the application. The controller may be implemented by a CPLD or FPGA. Based on the circuit structure disclosed by the application, the controller can control the attenuation value of the numerical control attenuation circuit according to the power of a received signal, so that when the power of the received signal is smaller than a preset threshold value, the numerical control attenuation circuit is in a 0 state and provides a 0dB attenuation value, and when the power of the received signal reaches the preset threshold value, the numerical control attenuation circuit is in an attenuation state and provides the preset attenuation value, so that a 1dB compression point of a receiving input is improved, and a receiving dynamic range is improved.

In the application, a numerical control attenuation circuit is realized by adopting a 1-bit digital positive control attenuator chip, a radio-frequency signal input end and a radio-frequency signal output end of the 1-bit digital positive control attenuator chip are respectively connected with two adjacent stages of pre-stage amplifiers, a control end of the 1-bit digital positive control attenuator chip is connected with a controller, an attenuator providing a preset attenuation value and a selector switch are arranged in the 1-bit digital positive control attenuator chip, the control end controls the action of the selector switch in the chip, and when the selector switch is in one state, the radio-frequency signal input end and the radio-frequency signal output end of the chip are directly connected to enable the chip to be in a 0 state and provide a 0dB attenuation value; when the switch is in another state, the attenuator is connected between the radio frequency signal input end and the radio frequency signal output end, so that the chip is in an attenuation state and provides a preset attenuation value.

The application illustrates the effectiveness of this structure in the following example:

it is assumed that the linear gains of the first stage amplifier V1 and the second stage amplifier V2 are both 15 dB. The input 1dB compression point of the first stage amplifier V1 is 0dBm and the input 1dB compression point of the second stage amplifier V2 is 5 dBm. The noise figure of the first stage amplifier V1 is 1dB and the noise figure of the second stage amplifier V2 is 2 dB. In a conventional circuit, i.e., without a digitally controlled attenuator circuit, the received noise figure is about 1.07dB, as calculated by simulation, with an input 1dB compression point of-10 dBm (limited by the second stage amplifier V2).

In the structure shown in fig. 1, when the digitally controlled attenuator circuit is added to the front-stage circuit, taking the attenuation state of the digitally controlled attenuator circuit to provide a 10dB attenuation value as an example, the digitally controlled attenuator circuit in fig. 1 may be implemented by a commercially available chip with a model number of HMC802ALP3E, the structure of which is shown in fig. 2, a radio frequency signal input terminal RF1 of the chip is connected to an output terminal of the first-stage amplifier V1, a radio frequency signal output terminal RF2 is connected to an input terminal of the second-stage amplifier V2, and a control terminal V0 of the chip is connected to the controller, and when the controller receives a high level signal (the level amplitude is +2V to +5V), the chip is in a 0 state and provides a 0dB attenuation value; when the controller receives a low level signal (0V- +0.8V), the chip is in an attenuation state and provides a 10dB attenuation value, the ze numerical control attenuation circuit can be switched between a 0dB state and a 10dB state, and the insertion loss corresponding to the two attenuation states is 0.5dB and 10.5dB respectively considering the inherent 0 state insertion loss (about 0.5dB) of the numerical control attenuation circuit.

The controller controls the digitally controlled attenuation circuit to provide a 0dB attenuation value when the power of the received signal is less than-10 dBm, and the noise figure is about 1.08dB (without substantially affecting the sensitivity of the receiving system, the operating state is consistent with that of the conventional receiving system) by simulation calculation. When the power of the received signal is more than or equal to-10 dBm, the controller controls the numerical control attenuation circuit to provide a 10dB attenuation value, and through simulation calculation, the noise coefficient is about 2.4dB, and the input 1dB compression point is 0dBm (limited by a first-stage amplifier V1). It is thus clear that compare conventional circuit, the utility model discloses a receive dynamic range can improve about 10dB, can satisfy the system requirement that input 1dB compression point is higher than-5 dBm. And the higher dynamic range can be obtained by reasonably designing the attenuation of the two-stage amplifier and the numerical control attenuation circuit.

The applicant needs to state that the controller may relate to a control algorithm when controlling the digital controlled attenuation circuit according to power, but the application claims a circuit structure of a preceding stage circuit, based on the circuit structure disclosed in the application, a person skilled in the art can undoubtedly implement the above control algorithm, and the state of the digital controlled attenuation circuit controlled by the controller according to the input power is a more conventional control process, so the application does not request protection of a specific control algorithm.

What has been described above is only a preferred embodiment of the present application, and the present invention is not limited to the above embodiments. It is to be understood that other modifications and variations directly derivable or suggested by those skilled in the art without departing from the spirit and scope of the present invention are to be considered as included within the scope of the present invention.

Claims

1. A novel pre-stage circuit for improving the dynamic range of a receiving system is characterized in that the novel pre-stage circuit comprises a plurality of stages of pre-stage amplifiers which are sequentially connected in series, the input end of a formed series circuit is used as the input end of the novel pre-stage circuit to obtain a receiving signal, the output end of the series circuit is used as the output end of the novel pre-stage circuit to be connected with a receiving system post-stage circuit, and a numerical control attenuation circuit is further connected in series between the plurality of stages of pre-stage amplifiers; the input end of the power detection circuit is connected with the input end of the novel pre-stage circuit, the output end of the power detection circuit is connected with the controller, the controller is connected with and controls the control end of the numerical control attenuation circuit, and the numerical control attenuation circuit is in a 0 state and provides a 0dB attenuation value or is in an attenuation state and provides a preset attenuation value under the action of a signal of the control end.

2. The novel pre-stage circuit according to claim 1, wherein the digitally controlled attenuator circuit is implemented by using a 1-bit digitally controlled attenuator chip, a radio frequency signal input terminal and a radio frequency signal output terminal of the 1-bit digitally controlled attenuator chip are respectively connected to two adjacent pre-stage amplifiers, and a control terminal of the 1-bit digitally controlled attenuator chip is connected to the controller.