CN86108783A - Saturated detector - Google Patents
Saturated detector Download PDFInfo
- Publication number
- CN86108783A CN86108783A CN 86108783 CN86108783A CN86108783A CN 86108783 A CN86108783 A CN 86108783A CN 86108783 CN86108783 CN 86108783 CN 86108783 A CN86108783 A CN 86108783A CN 86108783 A CN86108783 A CN 86108783A
- Authority
- CN
- China
- Prior art keywords
- transistor
- amplitude
- signal
- carrier frequency
- intermediate frequency
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Landscapes
- Amplifiers (AREA)
Abstract
Saturated detector is about the amplitude-modulated wave demodulation techniques, uses in a kind of radio receiver, amplitude-modulated wave is carried out the transistor circuit of envelope detection.This wave detector uses transistor to make detecting element, and its quiescent point is placed little saturation condition, curbs the half period of amplitude-modulated wave with the saturation region, detects other half period with the amplification region.Have the efficient height, distortion is little, the simply outstanding advantage of circuit.
Description
The invention relates to the amplitude-modulated wave demodulation techniques, use in a kind of radio receiver, amplitude-modulated wave is carried out the transistor circuit of envelope detection.
Existing transistor envelope detector, quiescent point is in the lightly conducting state, or the amplification region (in the CB section among Fig. 1-a) of close cut-off state, so distortion is big, efficient is low.The synchronous detector circuit is too complicated.
Existing transistor envelope detector, the detection load generally has only one, it is the modulation signal load, this load can not take into account the requirement of intermediate frequency (carrier frequency) signal, and often because the effect of intermediate frequency (carrier frequency) filter makes the impedance of this load for intermediate frequency (carrier frequency) signal, little of negligible degree, this all is disadvantageous for wave detector itself and prime intermediate frequency (carrier frequency) amplifier, and gain is descended.
Purpose of the present invention, a kind of efficient height, little, the simple amplitude-modulated wave envelope detector of circuit of distortion are provided, a kind of two loads that have are provided simultaneously, it is modulation signal load and intermediate frequency (carrier frequency) signal load, therefore it is higher to gain, or to the very little aforementioned wave detector of prime intermediate frequency (carrier frequency) amplifier gain influence.
Solution of the present invention, use transistor to make detecting element, and this transistor quiescent point roughly is arranged on little saturation condition, or the amplification region or the saturation region of approaching little saturation point, curb the half period of amplitude-modulated wave with the saturation region, detect other half period with the amplification region.This wave detector is called saturated detector, and this transistor is called saturated detection tube.
Such scheme can use one or two saturated detection tubes.When using two saturated detection tubes, must be connected into the differential type circuit, and insert at collector loop and to have centre tapped intermediate frequency (carrier frequency) transformer.This is called the differential type saturated detector.
The input amplitude-modulated signal of aforementioned schemes is called the amplifying type saturated detector from the base stage or the emitter input of saturated detection tube.Also the input amplitude-modulated signal can be coupled to the collector electrode of saturated detection tube, this is called the clamping type saturated detector.The coupled modes that alleged coupling means that direct coupling, intermediate frequency (carrier frequency) are transformer coupled, capacitive coupling, inductance coupling high, band pass filter coupling etc. are low-resistance to intermediate frequency (carrier frequency) signal.
The saturated detector of aforementioned schemes between the collector electrode and intermediate frequency (carrier frequency) filter circuit of saturated detection tube, inserts intermediate frequency (carrier frequency) transformer, as the load of intermediate frequency (carrier frequency) signal.This is called branch load saturation wave detector.
Fig. 1-a is that (test condition: power source voltage Vcc=10V, collector resistance Rc=10K, transistor use, 3DG6) for the inversion cuver of transistor emitter junction voltage U be and collector current Ic.The OC section is a cut-off region, and the CA section is the amplification region, and the AD section is the saturation region, and the A point is little saturation point.The amplifying type saturated detector utilizes the AD section to curb the half period of amplitude-modulated wave, utilizes the BA section to detect and amplifies other half period (as long as reasonable in design, generally can not enter the CB section).Because BA section linearity is fine, and the BAD section is a more satisfactory broken line, so detection distortion is very little, efficient is very high, has higher gain simultaneously.
Fig. 1-b is the output characteristic curve of transistor base current fixedly time the (same Fig. 1 of test condition-a).The SQ section is saturation region (or claiming the clamper district), and the QF section is constant current district (amplification region just), and the Q point is little saturation point.The clamping type saturated detector utilizes the SQ section to curb the half period of (bypassing in other words) amplitude-modulated wave, utilizes the high characteristics of QF section transistor impedance to detect other half period.Because QF section linearity is fine, the SQF section is a more satisfactory broken line, so that the clamping type saturated detector also has a detection distortion is little, and the characteristics that efficient is high.
The differential type saturated detector, two saturated detection tube alternations are in saturation region and amplification region, and between positive and negative two half periods, the input and output impedance is symmetrical, and is very little to the influence of level before and after it to himself, and is the full-wave detection device.
Divide the load saturation wave detector owing to be provided with a load that impedance is very high for intermediate frequency (carrier frequency) signal, this load simultaneously is little of negligible degree to envelope signal, therefore the gain that can obviously improve saturated detector, or prime intermediate frequency (carrier frequency) amplifier gain.
Saturated detection tube quiescent point is selected on little saturation point, can improve the detectability to small and weak signal.Quiescent point is selected near amplification region or the saturation region little saturation point, can reduce background noise.Little quiescent current Ic when saturated should suitably select, and crosses lowly easily to enter the CB section, and too high then broken line characteristic variation generally should be got Ic=0.6mA～5mA.
Fig. 2-Fig. 9 is the physical circuit of eight kinds of saturated detectors, can use and make amplitude-modulated wave (intermediate frequency) envelope detector in the radio superheterodyne receiver.Also can use and in straight reciver, make amplitude-modulated wave (carrier frequency) envelope detector.
Fig. 2-a is that amplifying type divides the load saturation wave detector, and Fig. 2-b is its oscillogram.
Fig. 3 amplifies clamping type to divide the load saturation wave detector.
Fig. 4-a is that base stage is imported differential amplifying type and divided the load saturation wave detector, and Fig. 4-b is its oscillogram.
Fig. 5 is that emitter is imported differential amplifying type and divided the load saturation wave detector.
Fig. 6 is that direct coupled difference clamping type divides the load saturation wave detector.
Fig. 7 is that direct coupled difference amplification clamping type divides the load saturation wave detector.
Fig. 8 is that the capacitive coupling clamping type divides the load saturation wave detector.
Fig. 9 is that transformer coupled differential clamping type divides the load saturation wave detector.
Fig. 2-a is a first embodiment of the invention.BG
1Be saturated detection tube, R
1-R
6Constitute dc bias circuit and load circuit, suitably choose its resistance, make BG
1Quiescent point roughly is near little saturation condition (be among Fig. 1-a the A point), C
1, C
2Be to exchange shunt capacitance, wherein C
1Be mainly intermediate frequency (carrier frequency) signal path, C
3, C
4, R
6Be intermediate frequency (carrier frequency) filter circuit, ZB
1, ZB
2Be intermediate frequency (carrier frequency) transformer, Vcc is the power supply positive electrode.ZB
2Be connected on collector loop, as intermediate frequency (carrier frequency) signal load, the modulation signal load is approximately equal to R
5Input amplitude-modulated signal u λ is through ZB
1Be coupled to BG
1Base stage, positive half cycle signal is by BG
1The saturation region curb, negative half-cycle signal is through BG
1Amplify and paraphase, by collector electrode output, because ZB
2Bigger to intermediate frequency (carrier frequency) signal impedance, so BG
1Very high to the negative half-cycle signal gain, envelope signal also is exaggerated simultaneously, and passes through ZB smoothly
2, through C
3, C
4, R
6Remaining intermediate frequency (carrier frequency) of filtering and high order harmonic component, modulation signal is exported from end points (1).The input amplitude-modulated signal, BG
1Collector signal, envelope signal, output modulation signal waveform figure see (2) among Fig. 2-b, (3), (4), (5) respectively.
Fig. 3 circuit is second embodiment.BG
2Be saturated detection tube, quiescent point roughly is located at little saturation condition, BG
3Be intermediate frequency (carrier frequency) amplifier tube, R
7-R
13Constitute dc bias circuit, C
5, C
6, C
7Constitute alternating current path, C
8, C
9, R
12Constitute intermediate frequency (carrier frequency) filter circuit, ZB
3, ZB
4Be intermediate frequency (carrier frequency) transformer, wherein ZB
4One terminate at BG
2, BG
3Collector electrode on, tap meets C
8, R
12, as intermediate frequency (carrier frequency) signal load, and the modulation signal load should be the parallel connection of this grade output impedance and back level input impedance, also can be at C
9Two ends and connecting resistance are as the modulation signal load.Input amplitude-modulated signal u λ is through ZB
2Divide two-way, the one tunnel delivers to BG
2Emitter carries out the saturated detection of amplifying type, and BG is delivered on another road
3Carry out intermediate frequency (carrier frequency) and amplify, the intermediate frequency after the amplification (carrier frequency) signal is directly coupled to BG
2Collector electrode carries out the saturated detection of clamping type, and half-wave voltage signal is converged after the detection of last road.Because ZB
4Intermediate frequency (carrier frequency) signal there is very high impedance, so BG
2The half-wave voltage signal gain that self is detected is very high, simultaneously BG
3Intermediate-frequency gain also very high.The envelope signal that has been amplified simultaneously is because ZB
4Very little and pass through smoothly to its impedance, through C
8, C
9, R
12Filtering, modulation signal is exported from end points (6).
Fig. 4-a is the 3rd embodiment.BG
4, BG
5Be the saturated detection tube of pair of differential, quiescent point roughly is located at little saturation condition.Emitter circuit balance resistance R
16, constant-current source HI
2Base loop is connected to intermediate frequency (carrier frequency) transformer ZB
5, R
14Be base biasing resistor.Collector loop is connected to HI
1As DC load, R
15, C
10, C
11Constitute intermediate frequency (carrier frequency) filter circuit, intermediate frequency (carrier frequency) transformer ZB
6As intermediate frequency (carrier frequency) signal load, its two ends meet BG respectively
4, BG
5Collector electrode, centre cap meets C
10, R
15ZB
6Three effects are arranged, the one, give BG respectively
4, BG
5Intermediate frequency (carrier frequency) load is provided, the 2nd, to intermediate frequency (carrier frequency) signal with BG
4, BG
5Collector electrode keep apart, the 3rd, to BG
4, BG
5Direct current path and envelope signal path are provided.The modulation signal load is the parallel connection of this grade output impedance and back level input impedance, also can be at C
11The two ends parallel resistance is as the modulation signal load.Input amplitude-modulated signal u λ is through ZB
5Be divided into two with frequency, the same width of cloth, inversion signal, deliver to BG respectively
4, BG
5Base stage makes it alternation in amplification region and saturation region.Positive half cycle is (with BG
4Base voltage rises to positive half cycle) by BG
5Detect and amplify, negative half period is by BG
4Detect and amplify, like this at BG
4, BG
5On the collector electrode, ZB the half period signal alternately appears,
6Centre cap is promptly exported the full-wave detection signal that is at half than collector signal amplitude, through C
10, C
11, R
15Filtering, modulation signal is exported by end points (7).Input amplitude-modulated signal, BG
5Collector signal, BG
4Collector signal, ZB
6Centre cap signal, output modulation signal waveform figure see (8) among Fig. 4-b, (9), (10), (11), (12) respectively.
Fig. 5 is the 4th embodiment.The difference of this example and Fig. 4-a is that input amplitude-modulated signal u λ is from saturated detection tube BG
6, BG
7Emitter input, modulation signal is from end points (13) output, all the other are same with Fig. 4-a.
The 5th embodiment sees Fig. 6 .BG
10, BG
11Be saturated detection tube, quiescent point roughly is located at little saturation condition (being Q point among Fig. 1-b).BG
8, BG
9It is intermediate frequency (carrier frequency) amplifier tube.HI
5, HI
6It is constant-current source.Input amplitude-modulated signal u λ is through intermediate frequency (carrier frequency) transformer ZB
9, be coupled to BG
9, BG
8Base stage is amplified the back by BG
9, BG
8Two collector electrodes output inversion signal, and be directly coupled to BG
10, BG
11Collector electrode, the saturated detection of clamping type that makes it to hocket, the full-wave detection signal after the detection is from ZB
10Centre cap takes out, through C
14, C
15, R
23The filtering modulation signal is exported from end points (14).
The 6th embodiment sees Fig. 7.This example is to have increased C on the basis of Fig. 6
18And ZB
12, give saturated detection tube BG
14, BG
15Base stage provides the input amplitude-modulated signal, and the output modulation signal is exported from end points (15).BG
12, BG
14Base signal must same-phase.
The 7th embodiment sees Fig. 8.BG
16Be saturated detection tube, quiescent point roughly is in little state saturation condition, and constant-current source HI is the collector electrode DC load.Input amplitude-modulated signal u λ is through capacitor C
13Be coupled to BG
16Collector electrode carries out the saturated detection of clamping type, and envelope signal is by intermediate frequency (carrier frequency) transformer ZB
14, through C
19, C
20, R
27Filtering, modulation signal is exported from end points (16).ZB
14Be intermediate frequency (carrier frequency) signal load, R
28It is the modulation signal load.
Fig. 9 is an eighth embodiment of the invention.BG
17, BG
18Be the saturated detection tube of pair of differential, quiescent point roughly is located at little saturation condition.Input amplitude-modulated signal u λ is through intermediate frequency (carrier frequency) transformer ZB
15Be divided into two inversion signals and be added to BG respectively
17, BG
18Collector electrode carries out the saturated detection of clamping type, and the full-wave detection signal after the detection is from ZB
15The secondary centre tap is taken out, through C
21, C
22, R
29Filtering, modulation signal is exported from end points (17).ZB
15Remove and possess ZB among Fig. 4-a
6Three functions outside, also possess simultaneously input signal u λ be coupled to BG
17, BG
18The function of collector electrode.R
30It is the modulation signal load.
Claims (5)
1, a kind of amplitude-modulated wave envelope detector that uses transistor to make detecting element is characterized in that the quiescent point of this transistor roughly is in little saturation condition, curbs the half period of amplitude-modulated wave with the saturation region, detects other half period with the amplification region.
2, a kind of use transistor is made detecting element, and the quiescent point of this transistor roughly is in the amplitude-modulated wave envelope detector of little saturation condition, it is characterized in that, has two transistors and makes detecting element, is connected into the differential type circuit.
According to the wave detector of claim 2, it is characterized in that 3, collector loop inserts and has centre tapped intermediate frequency (carrier frequency) transformer.
4, a kind of use transistor is made detecting element, and the quiescent point of this transistor roughly is in the amplitude-modulated wave envelope detector of little saturation condition, it is characterized in that, the input amplitude-modulated signal is coupled to the collector electrode of this transistor.
5, a kind of use transistor is made detecting element, the quiescent point of this transistor roughly is in the amplitude-modulated wave envelope detector of little saturation condition, it is characterized in that, between the collector electrode of this transistor and intermediate frequency (carrier frequency) filter circuit, seal in intermediate frequency (carrier frequency) transformer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 86108783 CN86108783A (en) | 1986-12-31 | 1986-12-31 | Saturated detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 86108783 CN86108783A (en) | 1986-12-31 | 1986-12-31 | Saturated detector |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN86108783A true CN86108783A (en) | 1988-07-20 |
Family
ID=4804055
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 86108783 Pending CN86108783A (en) | 1986-12-31 | 1986-12-31 | Saturated detector |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN86108783A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102098249A (en) * | 2010-12-17 | 2011-06-15 | 三维通信股份有限公司 | Real-time detection circuit for radiofrequency envelope |
| CN102882821A (en) * | 2012-09-13 | 2013-01-16 | 清华大学 | On-off keying (OOK) radio frequency receiver |
| CN102879625A (en) * | 2012-09-07 | 2013-01-16 | 清华大学 | Envelope detector with graphene transistor |
-
1986
- 1986-12-31 CN CN 86108783 patent/CN86108783A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102098249A (en) * | 2010-12-17 | 2011-06-15 | 三维通信股份有限公司 | Real-time detection circuit for radiofrequency envelope |
| CN102098249B (en) * | 2010-12-17 | 2013-10-09 | 三维通信股份有限公司 | Real-time detection circuit for radiofrequency envelope |
| CN102879625A (en) * | 2012-09-07 | 2013-01-16 | 清华大学 | Envelope detector with graphene transistor |
| CN102879625B (en) * | 2012-09-07 | 2014-08-06 | 清华大学 | Envelope detector with graphene transistor |
| CN102882821A (en) * | 2012-09-13 | 2013-01-16 | 清华大学 | On-off keying (OOK) radio frequency receiver |
| CN102882821B (en) * | 2012-09-13 | 2015-02-18 | 清华大学 | On-off keying (OOK) radio frequency receiver |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN1229633C (en) | Detection circuit | |
| US4887047A (en) | Current sense amplifier with low, nonlinear input impedance and high degree of signal amplification linearity | |
| CN109150123A (en) | A kind of small-signal pre-amplification circuit of high-gain | |
| CN1047707C (en) | Fsk receiver | |
| CN86108783A (en) | Saturated detector | |
| US4124819A (en) | Disturbing signal detection circuit | |
| US4513209A (en) | Level detector | |
| US4307347A (en) | Envelope detector using balanced mixer | |
| US4110635A (en) | Amplifying circuit | |
| GB1575357A (en) | Quadrature type phase detectors | |
| EP0367184A2 (en) | First stage circuit for an optical receiver | |
| CN1233115A (en) | Infrared signal receiver with attenuating circuit | |
| CN109861647A (en) | A kind of low noise high-precision amplification circuit | |
| US4318050A (en) | AM Detecting circuit | |
| US6590379B2 (en) | Apparatus for detecting the envelope of an input signal | |
| CN101401300B (en) | Amplification stage | |
| CN1288606A (en) | Detector circuit | |
| SU1672552A1 (en) | Amplitude detector | |
| US3466558A (en) | Measuring apparatus | |
| JPS6149846B2 (en) | ||
| CN220173210U (en) | High-frequency constant-voltage carrier type charge pre-amplifying circuit based on field effect transistor | |
| KR950005161B1 (en) | Fm demodulator circuit | |
| Nash | Ask the Applications Engineer-28 | |
| SU1688376A1 (en) | Amplitude-modulated signal demodulator | |
| KR930005229Y1 (en) | Am detector for multisound broadcasting system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WD01 | Invention patent application deemed withdrawn after publication |