CN204517800U - A kind of digital demodulation superregenerative wireless receiver - Google Patents
A kind of digital demodulation superregenerative wireless receiver Download PDFInfo
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- CN204517800U CN204517800U CN201520112184.0U CN201520112184U CN204517800U CN 204517800 U CN204517800 U CN 204517800U CN 201520112184 U CN201520112184 U CN 201520112184U CN 204517800 U CN204517800 U CN 204517800U
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Abstract
The utility model discloses a kind of digital demodulation superregenerative wireless receiver, comprise reception antenna, low noise amplifier, superregenerator, blanking circuit and digital conditioning circuit; Wherein digital conditioning circuit comprises frequency-conversion circuit, band pass filter, voltage comparator and single-chip microcomputer.Different from traditional superregenerative wireless receiver detection demodulation mode, the feature that the utility model utilizes the frequency of this self-gravitation signal to change with the difference of receiver input signal, to input in single-chip microcomputer after this black out signal shaping, adopt digital processing method to carry out demodulation.Owing to adopting digital demodulation, this utility model efficiently solves in traditional OOK self-gravitation superregenerative wireless receiver and adopts the envelope detection mode of simulation to be easily disturbed the problem low with code check.
Description
Technical field
The utility model belongs to the technical field of wireless communication receiver, is specifically related to a kind of superregenerative wireless receiver.
Background technology
Superregeneration receiver a kind ofly relies on the change of internal oscillator Induction Peried to identify the device of input signal power, typical superregeneration receiver is primarily of reception antenna, low noise amplifier (Low Noise Amplifier, LNA), superregenerator (Super Regeneration Oscillator, SRO), envelope detection demodulator circuit and black out signal produce the formations such as circuit, as shown in Figure 1.
The core of superregeneration receiver is superregenerator.And superregenerator is actually the oscillator that is operated in intermittent oscillation state, chopper frequency is determined by black out signal.As shown in Figure 1, in self-gravitation mode superregeneration receiver, when superregeneration receiver receives signal, deliver in the superregenerative oscillating circuit of rear class after the LNA of signal through front end amplifies, superregenerator receives the signal of same frequency, oscillator triode quiescent point changes, circuit starts starting of oscillation, oscillator is started working, amplifying triode Q2 operating current increases, pierce circuit charges to C4 through inductance L 3, when charging voltage raises, triode Q2 emitter voltage raises, when voltage is elevated to the shutoff voltage of triode Q2, oscillator quits work, electric current diminishes, now emitting stage voltage is due to the discharge process of R4, start electric discharge, the emitter voltage of triode Q2 starts to reduce, when being reduced to the scope that can make triode Q2 conducting, oscillator is started working again, oscillating current strengthens, start again charging, triode turns off, triode starts intermittent work.If receive signal always, the intermittent work of oscillator continues to carry out always.The frequency of this intermittent work is by the discharge and recharge Time dependent of RC.The signal amplitude received is stronger, and oscillator operation electric current is larger, and the RC discharge and recharge time is faster.When not receiving input signal, when namely inputting " 0 " signal, the Induction Peried of oscillator within each resting period is a metastable value; When an incoming signal is received, when namely inputting " 1 ", the Induction Peried of oscillator within each resting period will shorten, therefore, the envelope of the self-gravitation signal that oscillator exports having, no signal time there will be difference, the modulation signal of input is by rear class envelope detection circuit according to envelope difference demodulation out.
In envelope detection in traditional superregenerative wireless receiver and demodulator circuit, first carry out the extraction of envelope.As Fig. 1, superregenerator output from black out signal, through the high-frequency oscillation signal of band pass filter more than the filtering 300MHz of R8, R9, C10 and C11 composition, after the black out signal of more than 500KHz and DC influence, the envelope extracted that is data-signal, but its amplitude is very faint, and be mingled with noise, so need carry out amplifying thus supply follow-up comparator to compare, recover initial data.LM358 amplifier (or other 358 serial amplifier) is generally adopted to complete at this, the high gain operational amplifier of it is built-in two single power supplies.Wherein 5 pin, 6 pin and 7 pin apply to the in-phase end of amplifier respectively, and end of oppisite phase and output, add R14, and R15, C12 constitute in-phase proportion integral amplifier, for the amplification of signal and the integration with pulse; And 3 pin, 2 pin and 1 pin apply to the in-phase end of comparator respectively, end of oppisite phase and output, add resistance R10, R11, R12 and R13 and constitute homophase hysteresis comparator, thus recover initial data.
But in the discrete detection demodulation module of traditional superregenerative, because electric capacity in in-phase proportion integral amplifier is comparatively large, therefore the discharge and recharge time is longer, causes message transmission rate to be difficult to improve.In addition, voltage compare can be worsened from external interference such as power supply and plate levels on the impact of signal comparator threshold value, thus reduce the precision of demodulator circuit, and the inter-symbol interference problem that filter filtering pulse signal causes also will reduce the precision of demodulation.Although this suitably can be alleviated by reducing extinguishing frequency, this certainly will will reduce message transmission rate again.
Summary of the invention
Goal of the invention: for above-mentioned prior art, proposes a kind of digital demodulation superregenerative wireless receiver, solves superregenerative chip tradition envelope detection circuit and is easily disturbed the problem low with code check.
Technical scheme: a kind of digital demodulation superregenerative wireless receiver, comprises reception antenna, low noise amplifier, superregenerator, blanking circuit and digital conditioning circuit; Described digital conditioning circuit comprises frequency-conversion circuit, band pass filter, voltage comparator and single-chip microcomputer; Described frequency-conversion circuit is used for carrying out difference frequency process to the self-gravitation signal that described superregenerator exports; Described band pass filter is used for carrying out high-frequency signal filtering to frequency-conversion circuit output signal; Described voltage comparator is used for converting band pass filter output signal to single-chip microcomputer discernible digital signal; Described single-chip microcomputer is used for the frequency of the digital signal exported according to voltage comparator, realize the demodulation of described digital demodulation superregenerative wireless receiver input signal, be specially: when the frequency of the digital signal that voltage comparator exports is greater than threshold value A, obtain receiver and be input as " 1 " signal, when the frequency of the digital signal that voltage comparator exports is less than or equal to threshold value A, obtains receiver and be input as " 0 " signal.
As preferred version of the present utility model, described threshold value A=P1-K+20KHz, wherein P1 be described digital demodulation superregenerative wireless receiver when being input as " 0 " signal blanking circuit output from black out signal frequency values.
As preferred version of the present utility model, described threshold value A=P1-K+40KHz, wherein P1 be described digital demodulation superregenerative wireless receiver when being input as " 0 " signal blanking circuit output from black out signal frequency values.
Beneficial effect: different from traditional superregenerative wireless receiver detection demodulation mode, a kind of digital demodulation superregenerative wireless receiver of the present utility model, the self-gravitation signal utilizing blanking circuit to export output frequency when receiver is input as " 0 " signal is fixed in a certain frequency range, and the feature that output frequency is relatively high when receiver is input as " 1 " signal, according to the self-gravitation signal frequency in superregeneration receiver with the change of receiver " 0 " and " 1 " input signal and the feature changed, demodulation is carried out to signal.
At superregenerator output, self-gravitation signal is taken out, because now self-gravitation signal frequency is higher, in order to reduce the difficulty of single-chip microcomputer process, by frequency-conversion circuit, difference frequency process is carried out to this signal, then filtering high-frequency signal, obtains the self-gravitation signal of low frequency.This self-gravitation signal compares amplification through voltage comparator again, and self-gravitation signal outputs to the I/O port of single-chip microcomputer after transforming digital signal.In order to avoid self-gravitation signal is when receiver is input as " 0 ", the erroneous judgement that interference signal causes, blanking circuit to be added after the frequency values of 20KHz with the difference of fundamental frequency signal frequency as single-chip microcomputer judgment threshold A output from black out signal frequency values P1, by the analysis of single-chip microcomputer to the frequency of self-gravitation signal, " 1 " signal is recorded as by higher than input signal during threshold value A, input signal lower than threshold value A is recorded as " 0 " signal, thus the demodulation of settling signal.Owing to adopting digital demodulation, this utility model efficiently solves in traditional OOK self-gravitation superregenerative wireless receiver and adopts the envelope detection mode of simulation to be easily disturbed the problem low with code check.
Accompanying drawing explanation
Fig. 1 is traditional OOK self-gravitation superregenerative wireless receiver circuit structure chart;
Fig. 2 is the utility model digital demodulation superregenerative wireless receiver circuit structure chart.
Embodiment
Below in conjunction with accompanying drawing the utility model done and further explain.
As shown in Figure 2, a kind of digital demodulation superregenerative wireless receiver, comprises reception antenna, low noise amplifier, superregenerator, blanking circuit and digital conditioning circuit.Wherein, reception antenna, low noise amplifier, superregenerator and blanking circuit are identical with structure in traditional OOK self-gravitation superregenerative wireless receiver; Digital conditioning circuit comprises frequency-conversion circuit, band pass filter, voltage comparator and single-chip microcomputer.
Wherein, the self-gravitation signal that frequency-conversion circuit is used for superregenerator exports carries out difference frequency process, is specifically realized by XOR gate.The fundamental frequency signal of self-gravitation signal and frequency K=560KHz is reduced frequency by the method for difference frequency, and this fundamental frequency signal can be produced by the single-chip microcomputer in digital conditioning circuit.Fundamental frequency signal selects the reason of 560KHz to be, when receiver wireless signal, is about 560KHz output from black out signal frequency; When receiver has signal to input, can 560KHz be greater than output from black out signal frequency, the highest at 630KHz.This XOR gate can export existing High-frequency and low-frequency signal, and high frequency is about 1MHz at signal, the frequency-splitting of low frequency signal and self-gravitation signal and fundamental frequency signal.
RC low pass filter selected by band pass filter, for carrying out high-frequency signal filtering to frequency-conversion circuit output signal, the black out signal of output low frequency, namely output frequency is lower than the signal within 200KHz, the high-frequency signal filtering of more than the 1MHz in being outputed signal by frequency-conversion circuit.
Voltage comparator selects the twin voltage of model LM393 to compare integrated circuit, and the low frequency signal for being exported by band pass filter converts the discernible digital signal of single-chip microcomputer to, and its reference voltage can be set to the amplitude of the intermediate point position of self-gravitation signal amplitude.Meanwhile, voltage comparator also carries out adjustment duty ratio to band pass filter output signal, controls signal dutyfactor about 50%.
The digital signal that voltage comparator exports directly is delivered on the I/O port of single-chip microcomputer, is calculated the frequency of input signal, realize the demodulation of digital demodulation superregenerative wireless receiver input signal by single-chip microcomputer timing.During the demodulation of chip microcontroller digital demodulation superregenerative wireless receiver input signal, when the frequency of the digital signal that voltage comparator exports is greater than threshold value A, obtain receiver and be input as " 1 " signal, when the frequency of the digital signal that voltage comparator exports is less than or equal to threshold value A, obtains receiver and be input as " 0 " signal.
In the present embodiment, if digital demodulation superregenerative wireless receiver is when being input as " 0 " signal, blanking circuit is P1=560KHz output from black out signal frequency values, this frequency values has the fluctuation being no more than 20KHz, after blanking circuit carries out difference frequency output from black out signal and 560KHz fundamental frequency signal, this fluctuation being no more than 20KHz is input to single-chip microcomputer after voltage comparator conversion, if single-chip microcomputer is 100us to the sampling period of input signal, now single-chip microcomputer can collect n pulse, and n equals 1 or 2.Namely blanking circuit is set in 580KHz output from black out signal frequency limit, for receiver is input as the situation of " 0 " signal below 580KHz frequency, more than 580KHz frequency for receiver is input as the situation of " 1 " signal.
In order to avoid the impact of the factors such as interference, add 20KHz tolerance, namely when the signal frequency of restriction input voltage comparator is within 40KHz, assert that receiver is input as " 0 " signal, be now that 100us single-chip microcomputer can collect at most (n+2) individual pulse in the sampling period, be namely no more than 4 pulses.So, when the sampling period is 100us, if the umber of pulse that single-chip microcomputer detects within a sampling period is greater than 4, assert that receiver is input as " 1 " signal.
The above is only preferred implementation of the present utility model; it should be pointed out that for those skilled in the art, under the prerequisite not departing from the utility model principle; can also make some improvements and modifications, these improvements and modifications also should be considered as protection range of the present utility model.
Claims (3)
1. a digital demodulation superregenerative wireless receiver, comprise reception antenna, low noise amplifier, superregenerator, blanking circuit and digital conditioning circuit, it is characterized in that: described digital conditioning circuit comprises frequency-conversion circuit, band pass filter, voltage comparator and single-chip microcomputer; Described frequency-conversion circuit is used for carrying out difference frequency process to the self-gravitation signal that described superregenerator exports, and its fundamental frequency signal frequency is K; Described band pass filter is used for carrying out high-frequency signal filtering to frequency-conversion circuit output signal; Described voltage comparator is used for converting band pass filter output signal to single-chip microcomputer discernible digital signal; Described single-chip microcomputer is used for the frequency of the digital signal exported according to voltage comparator, realize the demodulation of described digital demodulation superregenerative wireless receiver input signal, be specially: when the frequency of the digital signal that voltage comparator exports is greater than threshold value A, obtain receiver and be input as " 1 " signal, when the frequency of the digital signal that voltage comparator exports is less than or equal to threshold value A, obtains receiver and be input as " 0 " signal.
2. a kind of digital demodulation superregenerative wireless receiver according to claim 1, it is characterized in that: described threshold value A=P1-K+20KHz, wherein P1 be described digital demodulation superregenerative wireless receiver when being input as " 0 " signal blanking circuit output from black out signal frequency values.
3. a kind of digital demodulation superregenerative wireless receiver according to claim 1, it is characterized in that: described threshold value A=P1-K+40KHz, wherein P1 be described digital demodulation superregenerative wireless receiver when being input as " 0 " signal blanking circuit output from black out signal frequency values.
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| CN201520112184.0U CN204517800U (en) | 2015-02-15 | 2015-02-15 | A kind of digital demodulation superregenerative wireless receiver |
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| CN201520112184.0U CN204517800U (en) | 2015-02-15 | 2015-02-15 | A kind of digital demodulation superregenerative wireless receiver |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104702303A (en) * | 2015-02-15 | 2015-06-10 | 东南大学 | Digital demodulating super-regeneration wireless receiver |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104702303A (en) * | 2015-02-15 | 2015-06-10 | 东南大学 | Digital demodulating super-regeneration wireless receiver |
| CN104702303B (en) * | 2015-02-15 | 2017-03-22 | 东南大学 | Digital demodulating super-regeneration wireless receiver |
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Granted publication date: 20150729 Effective date of abandoning: 20170322 |
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