CN207801916U - Wireless digital broadcasting station receiving circuit - Google Patents
Wireless digital broadcasting station receiving circuit Download PDFInfo
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- CN207801916U CN207801916U CN201721875499.6U CN201721875499U CN207801916U CN 207801916 U CN207801916 U CN 207801916U CN 201721875499 U CN201721875499 U CN 201721875499U CN 207801916 U CN207801916 U CN 207801916U
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Abstract
The utility model is related to a kind of wireless digital broadcasting station receiving circuit, including：Receive preprocessing module, superhet down conversion module, the first phase shifter, IQ down conversion modules, baseband modem.Preprocessing module is received to carry out pre-selection filtering to the radio frequency signal received and amplify, it exports ultrahigh-frequency signal to superhet down conversion module and carries out superhet down coversion and filtering, it is the orthogonal roads I intermediate-freuqncy signal and the roads Q intermediate-freuqncy signal to export filtered intermediate-freuqncy signal to the first phase shifter phase shift branch, the roads I intermediate-freuqncy signal and the roads Q intermediate-freuqncy signal down-convert to the roads I zero intermediate frequency signals and the roads Q zero intermediate frequency signals for the second time in IQ down conversion modules, after through baseband modem demodulate be sent into processor handled.The wireless digital broadcasting station receiving circuit first carries out pre-selection filtering and signal amplification after receiving radio frequency signal, improves receiving sensitivity, makes communications apart from longer, can carry out the wireless differential data transmission stablized over long distances in the wild.
Description
Technical field
The utility model is related to wireless communication fields, more particularly to a kind of wireless digital broadcasting station receiving circuit.
Background technology
Currently, Global Satellite Navigation System (GNSS) is applied in technical field of mapping, needed in mapping equipment
It is provided with the wireless digital broadcasting station for the GNSS differential datas for being used for transmission superfrequency (UHF).Wireless digital broadcasting station includes number
According to radiating circuit and data receiver circuit.
Traditional RF receiving circuit, by mixing, amplification and demodulation, obtains baseband signal for receiving radiofrequency signal.
Include mainly：Stenode circuit, zero intermediate frequency formula receiving circuit, nearly zero intermediate frequency receiving circuit.It is being used for transmission superfrequency
(UHF) in the R＆D process of the wireless digital broadcasting station of GNSS differential datas, inventor has found in traditional RF receiving circuit
At least there are the following problems：Conventional wireless data radio station receiving sensitivity is low, it is difficult to carry out stablizing for a long time, over long distances in the wild
Wireless differential data transmission.
Utility model content
Based on this, it is necessary to it is low for conventional wireless data radio station receiving sensitivity, it is difficult to carry out long-time, length in the wild
The problem of wireless differential data transmission of stable distance, provides a kind of wireless digital broadcasting station receiving circuit.
To achieve the goals above, the utility model embodiment provides a kind of wireless digital broadcasting station receiving circuit, wherein
Including：
Preprocessing module is received, for carrying out pre-selection filtering and power amplification, output to the radio frequency signal received
Ultrahigh-frequency signal；
Superhet down conversion module is connect with preprocessing module is received, for ultrahigh-frequency signal under superhet become
Frequency simultaneously filters, and exports filtered intermediate-freuqncy signal；
First phase shifter is connect with superhet down conversion module, defeated for by filtered intermediate-freuqncy signal phase shift and branch
Go out the orthogonal roads I intermediate-freuqncy signal and the roads Q intermediate-freuqncy signal；
IQ down conversion modules are connect with the first phase shifter, for being carried out respectively to the roads I intermediate-freuqncy signal and the roads Q intermediate-freuqncy signal
Down coversion exports I road zero intermediate frequency signals and the roads Q zero intermediate frequency signals；
Baseband modem is connect with IQ down conversion modules, for the roads I zero intermediate frequency signals and the roads Q zero intermediate frequency signals
It is demodulated, and exports demodulated signal to processor.
Receiving preprocessing module in one of the embodiments, includes：Concatenated prefilter and the first amplifier；
For carrying out pre-selection filtering to the radio frequency signal that reception antenna receives, the first amplifier is used for prefilter
It is amplified to preselecting filtered signal, exports ultrahigh-frequency signal.
Prefilter is low-pass filter in one of the embodiments, and the first amplifier is low-noise variable gain
Amplifier.
Receiving preprocessing module in one of the embodiments, further includes：RF switch, RF switch are connected on preposition filter
Between wave device and the first amplifier.
Superhet down conversion module includes in one of the embodiments,：First frequency mixer, the first local vibration source and first
Filter；
First local vibration source is for generating RF local oscillator signal；
First frequency mixer is used for the radio frequency of ultrahigh-frequency signal and the output of the first local vibration source to receiving preprocessing module output
Local oscillation signal carries out Frequency mixing processing, and ultrahigh-frequency signal is down-converted to intermediate-freuqncy signal；
First filter is used for the intermediate-freuqncy signal that is exported to the first frequency mixer and is filtered, and by filtered intermediate frequency
Signal is exported to the first phase shifter.
First filter is bandpass filter in one of the embodiments,.
The roads I intermediate-freuqncy signal is 0 degree of phase shift signal of filtered intermediate-freuqncy signal, the roads Q intermediate frequency in one of the embodiments,
Signal is 90 degree of phase shift signals of filtered intermediate-freuqncy signal.
IQ down conversion modules include in one of the embodiments,：The roads I frequency mixer, the roads Q frequency mixer, the second local vibration source with
And second phase shifter；
Second local vibration source is for generating intermediate frequency local oscillator signal；
The intermediate frequency local oscillator signal of second the second local vibration source of phase shifter pair output carries out phase shift and branch, 0 degree of phase shift of output
The intermediate frequency local oscillator signal of intermediate frequency local oscillator signal and 90 degree of phase shifts；
0 degree of phase shift of the roads the I intermediate-freuqncy signal and the output of the second phase shifter that the roads I frequency mixer is used to export the first phase shifter
Intermediate frequency local oscillator signal is mixed, and the roads I intermediate-freuqncy signal is down-converted to the roads I zero intermediate frequency signals and is exported to baseband modulation and demodulation
Device；
90 degree of phase shifts of the roads the Q intermediate-freuqncy signal and the output of the second phase shifter that the roads Q frequency mixer is used to export the first phase shifter
Intermediate frequency local oscillator signal be mixed, the roads Q intermediate-freuqncy signal is down-converted into the roads Q zero intermediate frequency signals and is exported to baseband modulation and demodulation
Device.
IQ down conversion modules further include in one of the embodiments,：Second filter, the second amplifier, third filtering
Device and third amplifier；
Second filter and the second amplifier are connected between the roads I frequency mixer and baseband modem；
Third filter and third amplifier are connected between the roads Q frequency mixer and baseband modem；
Second filter and third filter are low-pass filter in one of the embodiments, the second amplifier and the
Three amplifiers are variable gain amplifier.
Above-mentioned wireless digital broadcasting station receiving circuit, including receive preprocessing module, superhet down conversion module, the first phase shift
Device, IQ down conversion modules, baseband modem.It receives preprocessing module and pre-selection filtering is carried out to the radio frequency signal of reception
And power amplification, output ultrahigh-frequency signal to superhet down conversion module carries out superhet down coversion and filtering, after output filtering
Intermediate-freuqncy signal to the first phase shifter phase shift be the orthogonal roads I intermediate-freuqncy signal and the roads Q intermediate-freuqncy signal, in the roads I intermediate-freuqncy signal and the roads Q
Frequency signal down-converts to the roads I zero intermediate frequency signals and the roads Q zero intermediate frequency signals for the second time in IQ down conversion modules, after through baseband modulation
Demodulator, which is demodulated into demodulated signal and is output to processor, to be handled.The wireless digital broadcasting station receiving circuit is receiving less radio-frequency
Pre-selection filtering and signal amplification are first carried out after signal, improves receiving sensitivity, make communications apart from longer, it can be in the wild
Carry out the wireless differential data transmission stablized over long distances.
Description of the drawings
Fig. 1 is the structural framing figure of an embodiment wireless digital broadcasting station receiving circuit；
Fig. 2 is the circuit diagram of an embodiment wireless digital broadcasting station receiving circuit；
Fig. 3 is the circuit diagram of another embodiment wireless digital broadcasting station receiving circuit.
Specific implementation mode
The utility model is more fully retouched below with reference to relevant drawings for the ease of understanding the utility model,
It states.The preferred embodiment of the utility model is given in attached drawing.But the utility model can in many different forms come in fact
It is existing, however it is not limited to embodiment described herein.Make public affairs to the utility model on the contrary, purpose of providing these embodiments is
It is more thorough and comprehensive to open content.
It should be noted that when an element is considered as " connection " another element, it can be directly to separately
One element and it is in combination be integrated, or may be simultaneously present centering elements.Term as used herein " installation ", " one
End ", " other end " and similar statement are for illustrative purposes only.
Unless otherwise defined, all of technologies and scientific terms used here by the article is led with the technology for belonging to the utility model
The normally understood meaning of technical staff in domain is identical.Terminology used in the description of the utility model herein only be
The purpose of description specific embodiment, it is not intended that in limitation the utility model.Term " and or " used herein includes
Any and all combinations of one or more relevant Listed Items.
As shown in Figure 1, the structural framing figure of the wireless digital broadcasting station receiving circuit for an embodiment, the wireless digital broadcasting station
Receiving circuit is used to receive and demodulate the GNSS differential datas of superfrequency (UHF), can be used in and utilize Global Satellite Navigation System
In the mapping equipment surveyed and drawn.In the present embodiment, wireless digital broadcasting station receiving circuit includes：Reception preprocessing module 110,
Superhet down conversion module 120, the first phase shifter 130, IQ down conversion modules 140 and baseband modem 150.
It receives preprocessing module 110 and pre-selection filtering and power amplification is carried out to the radio frequency signal of reception, output is extra-high
Ultrahigh-frequency signal is down-converted to intermediate-freuqncy signal simultaneously by frequency signal to superhet down conversion module 120, superhet down conversion module 120
The filtering for carrying out corresponding wave band exports filtered intermediate-freuqncy signal to the first phase shifter 130, and the first phase shifter 130 is to filtered
Intermediate-freuqncy signal carries out phase shift processing and branch, exports the orthogonal roads I intermediate-freuqncy signal and the roads Q intermediate-freuqncy signal to IQ down conversion modules
The roads I intermediate-freuqncy signal is down-converted to the roads I zero intermediate frequency signals by 140, IQ down conversion modules 140, and the roads Q intermediate-freuqncy signal is down-converted to Q
Road zero intermediate frequency signals, export I road zero intermediate frequency signals and the roads Q zero intermediate frequency signals to baseband modem 150 is demodulated, and defeated
Go out demodulated signal to processor.
Specifically, " zero intermediate frequency signals " namely baseband signal in the roads I zero intermediate frequency signals and the roads Q zero intermediate frequency signals.
The wireless digital broadcasting station receiving circuit of the present embodiment first carries out pre-selection filtering after receiving radio frequency signal to it,
The selecting frequency characteristic for improving circuit prevents some interference signals from entering circuit, then carries out power to preselecting filtered signal
Amplification prevents the signal by pre-selection filtering because signal decaying cannot be identified by subsequent conditioning circuit, improves receiving sensitivity, enhance
Distance reception ability, disclosure satisfy that the reception to the wireless differential data of field long distance transmission.
Preprocessing module 110 is received, it is defeated for carrying out pre-selection filtering and power amplification to the radio frequency signal received
Go out ultrahigh-frequency signal.In one of the embodiments, with reference to figure 2, it includes concatenated prefilter to receive preprocessing module 110
111 and first amplifier 112；Prefilter 111 is used to carry out pre-selection filtering to the radio frequency signal that reception antenna receives,
First amplifier 112 is used to be amplified to preselecting filtered signal, output ultrahigh-frequency signal to superhet down conversion module
120。
Prefilter 111 is low-pass filter in one of the embodiments, and the first amplifier 112 is that low noise can
Variable-gain amplifier.The cutoff frequency of prefilter 111 is equipped with superhet down conversion module 120, by low
Pass filter can obtain the ultrahigh-frequency signal for needing to receive in receiving circuit, and rejection frequency, which is higher than, to be needed to receive in receiving circuit
The strong jamming clutter of ultrahigh-frequency signal frequency prevents out-of-band interference signal from entering circuit and blocks the first amplifier 112.
It further includes RF switch 113 to receive preprocessing module 110 in one of the embodiments, and RF switch 113 is connected
Between prefilter 111 and the first amplifier 112.Access for controlling wireless digital broadcasting station receiving circuit and open circuit.
Preferably, RF switch 113 is separately connected prefilter 111, the first amplifier 112, wireless digital broadcasting station hair
Transmit-receive radio road is closed at when processor controls RF switch 113 between prefilter 111 and the first amplifier 112, wireless data sending
Radio station receiving circuit is in running order；When processor control RF switch 113 closes at prefilter 111 and wireless data sending
Between the radiating circuit of radio station, wireless digital broadcasting station receiving circuit is off.
Superhet down conversion module 120, for carrying out superhet to receiving the ultrahigh-frequency signal that preprocessing module 110 exports
Down coversion simultaneously filters, and exports filtered intermediate-freuqncy signal.Superhet down conversion module 120 includes in one of the embodiments,：
First frequency mixer 121, the first local vibration source 122 and first filter 123；
First local vibration source 122 is for generating RF local oscillator signal；First frequency mixer 121 is used for receiving preprocessing module
The ultrahigh-frequency signal of 110 outputs and the RF local oscillator signal of the first local vibration source 122 output carry out Frequency mixing processing, by ultrahigh-frequency signal
Down-convert to intermediate-freuqncy signal；The intermediate-freuqncy signal that first filter 123 is used to export the first frequency mixer 121 is filtered,
And filtered intermediate-freuqncy signal is exported to the first phase shifter 130.
Specifically, the Frequency mixing processing that RF local oscillator signal and ultrahigh-frequency signal are carried out in the first frequency mixer 121 is namely
Superhet down coversion is carried out to ultrahigh-frequency signal, obtains an intermediate-freuqncy signal, this intermediate-freuqncy signal is RF local oscillator signal and spy
Difference frequency between high-frequency signal.For example, the frequency of RF local oscillator signal is fLO, the frequency of ultrahigh-frequency signal is fRF, then super outer
The frequency of the intermediate-freuqncy signal exported after poor down coversion is fIF=fLO-fRF.First filter 123 receives the output of the first frequency mixer 121
Intermediate-freuqncy signal, bandpass filtering is carried out to intermediate-freuqncy signal, improves the selecting frequency characteristic of circuit, enhances anti-interference ability, makes output
Intermediate-freuqncy signal frequency range within a predetermined range, is handled convenient for next step.
First filter 123 is bandpass filter in one of the embodiments,.
Preferably, bandpass filter bandwidth is 12KHz, and Out-of-band rejection ability is strong, and squareness factor is good, and filtering characteristic is more preferable,
Filtered intermediate-freuqncy signal frequency spectrum can be made cleaner.
The superhet that the first phase shifter 130 is used to export superhet down conversion module 120 in one of the embodiments,
Signal carries out phase shift processing and branch, exports the orthogonal roads I intermediate-freuqncy signal and the roads Q intermediate-freuqncy signal, and the wherein roads I intermediate-freuqncy signal exports
To the roads I frequency mixer, the roads Q intermediate-freuqncy signal is exported to the roads Q frequency mixer.The roads I intermediate-freuqncy signal is 0 degree of phase shift of filtered intermediate-freuqncy signal
Signal, the roads Q intermediate-freuqncy signal are 90 degree of phase shift signals of filtered intermediate-freuqncy signal.
IQ down conversion modules 140 carry out down coversion to the roads I intermediate-freuqncy signal and the roads Q intermediate-freuqncy signal respectively, export in the roads I zero
Frequency signal and the roads Q zero intermediate frequency signals.IQ down conversion modules 140 include：The roads I frequency mixer 141, the roads Q frequency mixer 142, the second local oscillator
Source 143 and the second phase shifter 144；Second local vibration source 143 is for generating intermediate frequency local oscillator signal；Second phase shifter 144 is to second
The intermediate frequency local oscillator signal of local vibration source output carries out phase shift and branch, export 0 degree of phase shift intermediate frequency local oscillator signal and 90 degree of phase shifts
Intermediate frequency local oscillator signal；The roads the I intermediate-freuqncy signal and the second phase shifter 144 that the roads I frequency mixer 141 is used to export the first phase shifter 130
The intermediate frequency local oscillator signal of 0 degree of phase shift of output is mixed, and the roads I intermediate-freuqncy signal is down-converted to the roads I zero intermediate frequency signals and is exported
To baseband modem 150；The roads the Q intermediate-freuqncy signal and the second phase shifter that the roads Q frequency mixer is used to export the first phase shifter 130
The intermediate frequency local oscillator signal of 90 degree of phase shifts of 144 outputs is mixed, and the roads Q intermediate-freuqncy signal is down-converted to the roads Q zero intermediate frequency signals simultaneously
It exports to baseband modem 150.
Specifically, the frequency and filtered intermediate-freuqncy signal of the intermediate frequency local oscillator signal that the second local vibration source 143 of setting generates
Centre frequency it is identical, the input signal of the roads I frequency mixer 141 be filtered intermediate-freuqncy signal 0 degree of phase shift signal and 0 degree of phase shift
Intermediate frequency local oscillator signal, their frequency is identical, therefore after 141 Frequency mixing processing of the roads I frequency mixer, filtered intermediate-freuqncy signal
0 degree of phase shift signal down-converts to the roads I zero intermediate frequency signals.Likewise, the input signal of the roads Q frequency mixer 142 is filtered intermediate frequency
The intermediate frequency local oscillator signal of 90 degree of phase shift signals and 90 degree of phase shifts of signal, their frequency is also identical, therefore through the roads Q frequency mixer
After 142 Frequency mixing processings, 90 degree of phase shift signals of filtered intermediate-freuqncy signal down-convert to the roads Q zero intermediate frequency signals.Wherein, it first moves
Phase device 130 and the second phase shifter 144 be single input, dual output 90-degree phase shifter.
Radiofrequency signal (such as cos (c)) and local oscillation signal (such as cos (l)) are subjected to Frequency mixing processing cos in traditional technology
(c) * cos (l)=1/2 [cos (c+l)-cos (c-l)] obtains two signals of cos (c+l) and cos (c-l) after mixing, and right
In the acquisition of modulated signal c, it is only necessary to one of signal can, therefore there are the waves of band resource in traditional technology
Take.In the present embodiment, 0 degree of phase shift signal of filtered intermediate-freuqncy signal and the intermediate frequency local oscillator signal of 0 degree of phase shift are mixed, will be filtered
90 degree of phase shift signals of the intermediate-freuqncy signal after wave and the mixing of the intermediate frequency local oscillator signal of 90 degree of phase shifts, can more easily obtain base band
Modulated signal under frequency.
For example, 0 degree of phase shift signal of filtered intermediate-freuqncy signal is expressed as sin (c), by the intermediate frequency local oscillator of 0 degree of phase shift
Signal is expressed as sin (l), and it is sin (c) * sin (l) that they carry out Frequency mixing processing in the roads I frequency mixer 141；By filtered intermediate frequency
90 degree of phase shift signals of signal are expressed as cos (c), the intermediate frequency local oscillator signal of 90 degree of phase shifts are expressed as cos (l), they are on the roads Q
It is cos (c) * cos (l) that frequency mixer 142, which carries out Frequency mixing processing,；Signal after two-way is mixed is added, so that it may to obtain the letter of c-l
Number it is expressed as cos (c-l)=cos (c) * cos (l)+sin (c) * sin (l).Therefore wireless digital broadcasting station provided in this embodiment
Receiving circuit can save band resource, can easily obtain the modulated signal under baseband frequency.
In other embodiments, the first phase shifter 130 and the second phase shifter 144 are using single input, the 90 degree of shiftings singly exported
Phase device, as shown in Figure 3.It is two-way in parallel, the i.e. roads I and the roads Q, the roads I through 123 filtered intermediate-freuqncy signal branch of first filter
The roads I frequency mixer 141 is connected, the roads Q connect concatenated first phase shifter 130, and the roads Q frequency mixer 142 is connected after phase shift.Second local vibration source
143 generate intermediate frequency local oscillator signals after branch be two-way, wherein all the way connection I roads frequency mixer 141 and filtered intermediate-freuqncy signal into
It goes and is mixed, the roads Q frequency mixer 142 is connected after the second phase shifter of another way connection 144 is shifted and through 130 phase shift of the first phase shifter
Filtered intermediate-freuqncy signal is mixed.
IQ down conversion modules 140 further include in one of the embodiments,：Second filter 145, the second amplifier 146,
Third filter 147 and third amplifier 148；Second filter 145 and the second amplifier 146 are connected on the roads I frequency mixer 141
Between baseband modem 150；Third filter 147 and third amplifier 148 are connected on the roads Q frequency mixer 142 and base band
Between modem 150.
Above-mentioned second filter 145 and third filter 147 are low-pass filter in one of the embodiments, second
Amplifier 146 and third amplifier 148 are variable gain amplifier.Second filter is added in IQ down conversion modules 140
145, the second amplifier 146, third filter 147 and third amplifier 148, can improve the choosing of IQ down conversion modules 140
Frequency characteristic enhances anti-interference ability, enables the roads the I zero intermediate frequency signals after filter and amplification and the roads Q zero intermediate frequency signals accurately quilt
Baseband modem 150 is demodulated into demodulated signal.
Second filter 145 and third filter 147 are set as low-pass filter, because of the inhibition energy of low-pass filter
Power is good, can enhance communication quality more effectively being filtered out with outer high fdrequency component.
In a specific embodiment, wireless digital broadcasting station receiving circuit includes：Prefilter 111, RF switch
113, the first amplifier 112, the first local vibration source 122, the first frequency mixer 121, first filter 123, the first phase shifter 130, the roads I
Frequency mixer 141, the roads Q frequency mixer 142, the second local vibration source 143, the second phase shifter 144, second filter 145, the second amplifier
146, third filter 147, third amplifier 148 and baseband modem 150.
Prefilter 111, RF switch 113, the first amplifier 112 are connected in series in one of the first frequency mixer 121
Input terminal；Another input terminal of first frequency mixer 121 connects the first local vibration source；The output end connection the of first frequency mixer 121
One end of one filter 123；The other end of first filter 123 connects the first phase shifter 130；Two of first phase shifter 130
Output end is separately connected an input terminal of the roads I frequency mixer 141, an input terminal of the roads Q frequency mixer 142；Second local vibration source
The input terminal of 143 the second phase shifters 144 of connection；Two output ends of the second phase shifter 144 are separately connected the roads I frequency mixer 141
Another input terminal of another input terminal, the roads Q frequency mixer 142；Concatenated second filter of output end connection of the roads I frequency mixer 141
Wave device 145 and the second amplifier 146；The output end of the roads Q frequency mixer 142 connects concatenated third filter 147 and third amplification
Device 148；The other end parallel connection of the other end and third amplifier 148 of second amplifier 146 accesses baseband modem 150.
Wherein, prefilter 111 is low-pass filter, and the first amplifier 112 is Low Noise Variable Gain Amplifier, the
One filter 123 is bandpass filter, and second filter 145 and third filter 147 are low-pass filter, the second amplifier
146 and third amplifier 148 be variable gain amplifier.
The processing procedure of radio frequency signal is as follows, and the radio frequency signal that reception antenna receives is sent to preposition filter
Wave device 111, prefilter 111 carry out pre-selection low-pass filtering to radio frequency signal, and send the superfrequency letter that filtering obtains
Number to the first amplifier 112, ultrahigh-frequency signal amplifies through the first amplifier 112；Later, the first frequency mixer 121 believes superfrequency
Number and the RF local oscillator signal that generates of the first local vibration source 122 be mixed, ultrahigh-frequency signal is down-converted to intermediate-freuqncy signal, first
Intermediate-freuqncy signal is sent into first filter 123 and carries out bandpass filtering by frequency mixer 121；Later, the first phase shifter 130 will be filtered
Intermediate-freuqncy signal carries out phase shift processing, is divided into two paths of signals in parallel, using 0 degree of phase shift signal of filtered intermediate-freuqncy signal as I
Road intermediate-freuqncy signal, using 90 degree of phase shift signals of filtered intermediate-freuqncy signal as the roads Q intermediate-freuqncy signal；Second local oscillator generates intermediate frequency sheet
It shaking and signal and is sent to the second phase shifter 144, the second phase shifter 144 is by intermediate frequency local oscillator signal phase shift and is divided into two paths of signals,
The intermediate frequency local oscillator signal of 0 degree of phase shift is sent into the roads I frequency mixer 141 to be mixed with the roads I intermediate-freuqncy signal, obtains the roads I zero intermediate frequency signals simultaneously
It is sent into second filter 145, the intermediate frequency local oscillator signal of 90 degree of phase shifts is sent into the roads Q frequency mixer 142 to be mixed with the roads Q intermediate-freuqncy signal,
It obtains the roads Q zero intermediate frequency signals and is sent into third filter 147；Second filter 145 and the second amplifier 146 are to the roads I zero intermediate frequency
Signal is sent to baseband modem 150, third filter 147 and third amplification after carrying out low-pass filtering and enhanced processing
Device 148 is sent to baseband modem 150 after carrying out low-pass filtering and enhanced processing to the roads Q zero intermediate frequency signals；Base band tune
Modulator-demodulator 150 demodulates the roads the I zero intermediate frequency signals after filter and amplification and the roads the Q zero intermediate frequency signals after filter and amplification, will
Demodulated signal is sent into processor and carries out subsequent processing.
The wireless digital broadcasting station receiving circuit of the present embodiment enhances selecting frequency characteristic, improves by the way that multiple filters are added
Anti-interference ability, meanwhile, the noise coefficient of the insertion loss and the first amplifier 112 that reduce prefilter 111 makes this reality
The noise coefficient of the wireless digital broadcasting station receiving circuit of example offer is applied within 1dB, enhances the receiving sensitivity of circuit.
In a specific embodiment, it is assumed that error rate BER 10-5, signal-to-noise ratio 15dB, it is assumed that code check is 19200
4FSK is modulated, and first filter 123 is bandpass filter, and bandwidth 12.5kHz, centre frequency 45MHz are sensitive according to receiving
Degree formula can calculate the receiving sensitivity of the present embodiment wireless digital broadcasting station receiving circuit.Calculation of Sensitivity formula is
Sensitivity=-174+NF+10lgB+10lgSNR
Wherein, NF is noise coefficient, B is signal bandwidth, SNR is demodulation signal-to-noise ratio.Therefore it can be obtained by above-mentioned data
Sensitivity=-174+1+41+15=-117dBm in the present embodiment, therefore wireless data sending provided by the utility model electricity
Platform receiving circuit can reach the receiving sensitivity of -117dBm, and receiving sensitivity is high, and transmission range is long.
In a specific embodiment, the first local vibration source 122 and the second local vibration source 143 are made of phase-locked loop circuit, locking phase
The local oscillation signal frequency spectrum that loop circuit generates is clean, and spuious small and frequency stability is high, and ideal mix can be obtained in mixing
Yupin effect.
Above example only expresses the several embodiments of the utility model, the description thereof is more specific and detailed, but simultaneously
Cannot the limitation to the utility model patent range therefore be interpreted as.It should be pointed out that for the ordinary skill of this field
For personnel, without departing from the concept of the premise utility, various modifications and improvements can be made, these belong to this
The protection domain of utility model.Therefore, the protection domain of the utility model patent should be determined by the appended claims.
Claims (10)
1. a kind of wireless digital broadcasting station receiving circuit, which is characterized in that including：
Preprocessing module is received, for carrying out pre-selection filtering and power amplification to the radio frequency signal received, output is extra-high
Frequency signal；
Superhet down conversion module is connect with the reception preprocessing module, for carrying out superhet to the ultrahigh-frequency signal
Down coversion simultaneously filters, and exports filtered intermediate-freuqncy signal；
First phase shifter is connect with the superhet down conversion module, is used for the filtered intermediate-freuqncy signal phase shift and is divided
Road exports the orthogonal roads I intermediate-freuqncy signal and the roads Q intermediate-freuqncy signal；
IQ down conversion modules are connect with first phase shifter, for respectively to the roads I intermediate-freuqncy signal and the roads Q intermediate frequency
Signal carries out down coversion, exports I road zero intermediate frequency signals and the roads Q zero intermediate frequency signals；
Baseband modem is connect with the IQ down conversion modules, for the roads I zero intermediate frequency signals and the roads Q zero
Intermediate-freuqncy signal is demodulated, and exports demodulated signal to processor.
2. wireless digital broadcasting station receiving circuit according to claim 1, which is characterized in that the reception preprocessing module packet
It includes：Concatenated prefilter and the first amplifier；
For carrying out pre-selection filtering to the radio frequency signal that reception antenna receives, described first puts the prefilter
Big device is used to be amplified to preselecting filtered signal, exports the ultrahigh-frequency signal.
3. wireless digital broadcasting station receiving circuit according to claim 2, which is characterized in that the prefilter is low pass
Filter, first amplifier are Low Noise Variable Gain Amplifier.
4. wireless digital broadcasting station receiving circuit according to claim 2, which is characterized in that the reception preprocessing module is also
Including：RF switch, the RF switch are connected between the prefilter and first amplifier.
5. wireless digital broadcasting station receiving circuit according to claim 1, which is characterized in that the superhet down conversion module
Including：First frequency mixer, the first local vibration source and first filter；
First local vibration source is for generating RF local oscillator signal；
First frequency mixer is used for the ultrahigh-frequency signal to the reception preprocessing module output and first local oscillator
The RF local oscillator signal of source output carries out Frequency mixing processing, and the ultrahigh-frequency signal is down-converted to intermediate-freuqncy signal；
The intermediate-freuqncy signal that the first filter is used to export first frequency mixer is filtered, and will filtering
The intermediate-freuqncy signal afterwards is exported to first phase shifter.
6. wireless digital broadcasting station receiving circuit according to claim 5, which is characterized in that the first filter is band logical
Filter.
7. wireless digital broadcasting station receiving circuit according to claim 1, which is characterized in that the roads I intermediate-freuqncy signal is filter
0 degree of phase shift signal of the intermediate-freuqncy signal after wave, the roads Q intermediate-freuqncy signal are 90 degree of shiftings of the filtered intermediate-freuqncy signal
Phase signals.
8. wireless digital broadcasting station receiving circuit according to claim 7, which is characterized in that the IQ down conversion modules packet
It includes：The roads I frequency mixer, the roads Q frequency mixer, the second local vibration source and the second phase shifter；
Second local vibration source is for generating intermediate frequency local oscillator signal；
Second phase shifter carries out phase shift and branch to the intermediate frequency local oscillator signal that second local vibration source exports, and exports 0 degree of shifting
The intermediate frequency local oscillator signal of the intermediate frequency local oscillator signal of phase and 90 degree of phase shifts；
I road intermediate-freuqncy signal and second phase shifter of the roads the I frequency mixer for being exported to first phase shifter are defeated
The intermediate frequency local oscillator signal of the 0 degree of phase shift gone out is mixed, and the roads I intermediate-freuqncy signal is down-converted to the roads I zero intermediate frequency
Signal is simultaneously exported to the baseband modem；
Q road intermediate-freuqncy signal and second phase shifter of the roads the Q frequency mixer for being exported to first phase shifter are defeated
The intermediate frequency local oscillator signal of the 90 degree of phase shifts gone out is mixed, and the roads Q intermediate-freuqncy signal is down-converted to the roads Q zero intermediate frequency
Signal is simultaneously exported to the baseband modem.
9. wireless digital broadcasting station receiving circuit according to claim 8, which is characterized in that the IQ down conversion modules are also wrapped
It includes：Second filter, the second amplifier, third filter and third amplifier；
The second filter and the second amplifier are connected between the roads I frequency mixer and the baseband modem；
The third filter and third amplifier are connected between the roads Q frequency mixer and the baseband modem.
10. wireless digital broadcasting station receiving circuit according to claim 9, which is characterized in that
The second filter and the third filter are low-pass filter, and second amplifier and third amplifier are can
Variable-gain amplifier.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108055049A (en) * | 2017-12-26 | 2018-05-18 | 广州中海达卫星导航技术股份有限公司 | Wireless digital broadcasting station receiving circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108055049A (en) * | 2017-12-26 | 2018-05-18 | 广州中海达卫星导航技术股份有限公司 | Wireless digital broadcasting station receiving circuit |
| CN108055049B (en) * | 2017-12-26 | 2024-01-12 | 广州中海达卫星导航技术股份有限公司 | Wireless data transmission radio receiving circuit |
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