CN100499615C - Residual side-band receiver and carrier releaser - Google Patents
Residual side-band receiver and carrier releaser Download PDFInfo
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- CN100499615C CN100499615C CNB2004100845803A CN200410084580A CN100499615C CN 100499615 C CN100499615 C CN 100499615C CN B2004100845803 A CNB2004100845803 A CN B2004100845803A CN 200410084580 A CN200410084580 A CN 200410084580A CN 100499615 C CN100499615 C CN 100499615C
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Abstract
It consists of: data processor that allows certain bandwidth of medium frequency passed through and makes digitalization, after the antenna selects required channel frequency and makes conversion to medium frequency; carrier recovering unit that takes size of pilot frequency in pass band signals as the required size, and recovers baseband, based on comparing result, after comparing power value of output signal from low-pass filter with preset threshold; synchronous demodulation unit for removing pilot frequency signal and extracting synchronized signal; noise removing unit for removing linear noise and remained phase noise by using synchronized signals; decoding unit for decoding baseband signal after noise filtering.
Description
Technical field
The present invention relates to Digital Television, specially refer to signal that reception modulates and transmit in residual sideband (VestigialSide Band:VSB) mode also the vestigial sideband reception machine and the carrier redactor thereof of primary carrier.
Background technology
Generally speaking, domestic in the U.S. and Korea S, the residual sideband mode of total alliance (Grand Alliance) is adopted to the standard of Digital Television (as: HDTV) load mode, it is when carrying out Modulation and Amplitude Modulation to signal, be in two sidebands that direction generates up and down of center with the carrier wave, the mode that the remainder when only the sideband signals that makes one of them direction significantly being decayed is modulated.That is, the frequency spectrum of a direction sideband by only taking base band is one of the mode in service band zone effectively to passband conversion and the mode that transmits.
At this moment, if the DC frequency spectrum of above-mentioned VSB modulator base band (base band) shifts to passband (pass band), then change over the tone frequency spectrum, this signal usually is known as pilot signal.That is, carry out VSB when modulation, in order in receiver, signal to be carried out accurate demodulation, and be written into pilot signal to aerial emission in TV station.
Fig. 1 is the simple structure chart of the transfer system of ordinary numbers TV.Randomizer (Randomizer) 101 produces the input data at random and exports to reed-solomon RS decoder 102, RS decoder 102 is to for carrying out that data inboard and that the outside channel coding import at random carry out that R-S decodes and after tax adds the odd even code of 20 bytes, exporting digital multiplexer 103 to.
Fig. 2 is the structure chart of detailed formation of VSB modulating unit of the emitter of Digital Television shown in Figure 1.
By the signal of the channel decoder (Channel Encoder) 201 that constitutes by randomizer shown in Figure 1 101, RS decoder 102, digital multiplexer 103, trellis code decoder 104, multiplexer 105, pilot plug-in unit 106, for carrying out the VSB modulating unit of VSB modulation by constituting by composite filter 202 and intermediate frequency modulator 203.At first, the signal by channel decoder 201 is for carrying out VSB modulation passing through composite filter (Complex filter) 202.At this moment, if decoded digital signal by composite filter 202, then relies on Hilbert (Hilbert) transducer and SRC with I﹠amp; The frequency modality conversion of Q signal becomes can carry out the form of VSB modulation.
Each I﹠amp for composite filter 202 outputs; Q signal if carry out in subtracter 204 two signals being deducted after the intermediate frequency Modulation, then can obtain the VSB intermediate-freuqncy signal of necessary bandwidth in intermediate frequency modulator 203.As above the VSB intermediate-freuqncy signal of Sheng Chenging in order to transmit with aerial ripple, convert wireless frequency (RF) passband signal that is intended to effectively transmit to via RF upconverter 205 after, transmits by antenna 206.
Fig. 3 is the structure chart of formation of the receiving system of common Digital Television.
Fig. 3 is the structure chart of formation of the digital television receiving apparatus of ATSC specification.Extract the passband signal of specific channel by tuner,, from the baseband signal of being reduced, carry out reduction of code clock and channel compensator and extract transmitting utilizing after the pilot signal of inserting sideband carries out carrier restoring.
The receiving system of the Digital Television of above-mentioned prior art design comprises: after the channel frequency of selecting to want by antenna 301, the VSB signal of the RF frequency band of institute's load on the above-mentioned channel frequency is carried out the tuner 302 of the 1st downward conversion to the frequency band-IF frequency band that uses easily in circuit common; The SAW (Surface Acoustic Wave) filter 303 that certain frequency band of the IF signal of output is passed through; The output band of SAW (Surface Acoustic Wave) filter 303 is carried out the IF processing unit 304 of conversion downwards the 2nd time to the signal of wanting in A/D converter 305; Analog output signal in the IF processing unit 304 is carried out digitized A/D converting unit 305; The digital signal of A/D converting unit 305 is converted to the carrier restoring unit 306 of baseband signal; In the output signal of carrier restoring unit 306, remove the DC remover 307 of pilot signal; In the output signal of DC remover 307, extract synchronizing signal and reduce the synchronous unit 308 of code clock; In the transmission signal of having removed the DC composition, remove the channel equalizer 309 of linear noise; In having removed the transmission signal of linear noise, remove the phase tracking device 310 of residual phase noise; Carry out the FEC unit 311 of the decode procedure opposite to transmitting signal with the digital channel coding of transmitting terminal.
At this, tuner 302, SAW (Surface Acoustic Wave) filter 303 and IF processing unit 304 can be called analog processing unit, can will carry out digitized A/D converting unit 305 to the analog output signal in the IF processing unit 304 that belongs to analog processing unit and analog processing unit is called digital processing element altogether.And DC remover 307 and synchronous unit 308 can be called the synchronous demodulation unit, and channel equalizer 309 and phase tracking device 310 can be called the noise removal unit.
Promptly, if receive with VSB mode modulated RF signal by antenna 301,302 of tuners are after the channel frequency that uses the heterodyne method modulation system to select to want, the VSB signal of the RF frequency band of load on the above-mentioned channel frequency is reduced to medium-frequency band (IF: generally be extensive use of 44MRHz or 43.75MHz) through locking, suitably filter out other channel signals.
And, with the go forward side by side output signal of tuner 302 of line output of the spectral transition of arbitrary channel to the IF frequency band of locking, by having adopted sound surface (Surface Acoustic Wave:SAW) filter 303 of the function of removing other band signal, removing noise signal and simulation integration filter.
At this moment, digital broadcast signal is lifted an example because at the intermediate frequency of 44MHz to the frequency band of 6MHz with interior all information that exist, so after SAW (Surface Acoustic Wave) filter 303 is only retained the frequency band of the 6MHz that has information that exports from tuner 302 and removed remaining interval, export IF processing unit 304 to.
(Carrier Recovery) 306 is demodulated to baseband signal (BaseBand) in the carrier restoring unit to be converted into the passband signal of digital signal, being demodulated on the signal of baseband signal, is the DC composition that the frequency of carrying out the pilot signal that carrier wave demodulation inserts then converts 0Hz at transmitting terminal.
At this, the effect of the DC composition that is generated has been performed, therefore the DC remover 307 by it is removed.
From the output of DC remover 307, extract and transmit the synchronizing signal that exists in the signal, in the synchronous unit 308 of reduction code clock, extract the information in synchronizing signal interval.At this moment, the information in the interval of the synchronizing signal that is generated is used in channel equalizer 309, phase tracking device 310 and the FEC unit 311 of rear end.
Removed the signal of DC composition, passed through channel equalizer 309 in order to remove the linear noise that exists in the analogue unit in transmitting channel and receiver.And, via the phase tracking device 310 that the residual phase noise of failing to remove in the obstruction is in front removed, in FEC unit 311, carry out and the opposite decode procedure of employed digital channel coding in transmitter unit.If this operation finishes, then the effect of the receiving element in the Digital Television is all over, and the transmission stream (Transport Stream) identical with the signal of importing to receiving element from transmitting terminal transmits to video and audio signal processing unit (not shown).
Fig. 4 is the structure chart of detailed formation of carrier restoring unit of the receiving system of Digital Television shown in Figure 3.
Fig. 4 is as the detailed structure view of the carrier restoring unit 306 in the structure chart of the formation of the receiving system of Fig. 3, is the relevant ordinary construction pie graph of carrying out when proposing Frequency Phase Lock loop (Frequency Phase Lock Loop) as carrier restoring unit 306 according to the ATSC specification.
The carrier restoring unit of digital television receiving apparatus is made of following: if passband (PassBand) analog signal is converted into the digital signal line output of going forward side by side, then make its 90 degree be inverted and convert to the Hilbert transducer of exporting after the Q signal of imaginary number character 402; After the processing time of the Q signal that postpones to be equivalent to be used for digital signal is converted to Hilbert transducer 402, the delayer 401 of the I signal of output real number character; The output signal of I, Q output signal and the voltage-controlled oscillator 410 of delayer 401 and Hilbert transducer 402 is multiplied each other, and synthesize the synthetic synergistic device 403 of output as I, the Q signal of base band; With by I signal low pass filter 404, delayer 406, code extractor 407, synergistic device 408, loop filter 409 and voltage-controlled oscillator (VCO) 410 constitute and be used to lock synthetic synergistic device 403 outputs base band I signal frequency frequency locked loop (Frequency LockLoop) and by Q signal low pass filter 405, synergistic device 408, the Frequency Phase Lock loop that loop filter 409 and voltage-controlled oscillator (VCO) 410 constitute and be made of the phased lock loop (Phase Lock Loop) of the phase place of the Q signal of the base band that is used to lock synthetic synergistic device 403 outputs.
At this, I signal low pass filter 404, delayer 406 and code extractor 407 detect frequency error (Error), and Q signal low pass filter 405 is detected phase error (Error) in measured frequency error.And the frequency error of I signal low pass filter 404, delayer 406 and code extractor 407 and the phase error of Q signal low pass filter 405 multiply each other by synergistic device 408, final calculated rate and phase error composition (control voltage).
So, loop filter 409 is removed the frequency content that comprises in frequencies and the phase error composition, then changes frequency of oscillation according to frequency and phase error composition (control voltage) and vibrate in voltage-controlled oscillator 410.
That is, loop oscillator 409 is the filtered baseband signal line output of going forward side by side only, and voltage-controlled oscillator 410 is according to the frequency of oscillation of output signal output through changing of loop filter 409.And, so change the frequency and the phase place of carrier wave and remove heterodyne (beat) frequency (being difference frequency or beat frequency) according to the frequency of oscillation through changing in the voltage-controlled oscillator 410.
That is, in carrier restoring unit 306, discrete phases from the output signal of SAW (Surface Acoustic Wave) filter 303 is carried out demodulation and locking (locking) frequency and phase place to I, the Q signal of base band.The centre frequency of voltage-controlled oscillator (VCO) 410 (for example: 46.690559MHz) is locked into intermediate frequency, the output of VCO410 in synthetic synergistic device 403 with the output multiplication of SAW (Surface Acoustic Wave) filter 303 and be demodulated to I, the Q channel signals (i (t), q (t)) of base band.
At this moment, the pilot carrier frequency that inserts in the emitter must accurately be present in intermediate frequency (for example: 46.690559MHz), remaining receiving system is just normally carried out action in the output of SAW (Surface Acoustic Wave) filter 303.A lot of when generally speaking, being not 46.690559MHz.
Yet, because the output frequency of voltage-controlled oscillator 410 is locked in 46.690559MHz, so the output frequency of pilot tone is not to be under the situation of 46.690559MHz in SAW (Surface Acoustic Wave) filter 303, then there is heterodyne (beat) frequency that is equivalent to the difference of two frequencies of output in the synthetic synergistic device 403.In order to remove above-mentioned one-tenth beat frequency, frequency of utilization phased lock loop.That is, change, make the frequency and the phase change of carrier wave and remove into beat frequency by the frequency of oscillation that makes voltage-controlled oscillator 410.Thereby finding out the frequency of oscillation variation and the size that make voltage-controlled oscillator 410 then is the purpose of Frequency Phase Lock loop.
The form that FPLL possesses by the loop that is used to make frequency lock (loop) and is used to make the loop of phase place (phase) locking to combine.
In Fig. 4, the automatic frequency of being realized by low pass filter 404, delayer 406 is regulated filter (AFC Filter:Auto Frequency Control Filter) and is become by the loop that code detector 407, synergistic device 408, loop filter 409, voltage-controlled oscillator 410 and synthetic synergistic device 403 constitute and is used to make frequency locked loop (FLL), and the loop that is made of Q signal low pass filter 405, synergistic device 408, loop filter 409, voltage-controlled oscillator 410 and synthetic synergistic device 403 becomes and is used to make phased lock loop (PLL).
The S-curve (curve) that generates according to phased lock loop as shown in Figure 5.
On the one hand, as previously mentioned, the carrier restoring algorithm that the Frequency Phase Lock loop constitutes possesses the form that the frequency of the output frequency of voltage-controlled oscillator 410 and pilot signal is coincide.Thereby under the pilot signal inaccuracy of I signal ground was present in situation among the DC, the position of seeking on the frequency spectrum of pilot signal was very important, and the data component outside the pilot signal can't give the carrier wave demodulation information necessary.
Thereby, in order to remove carrier wave demodulation institute unnecessary data composition, use I signal low pass filter 404.
But, under the situation that the pilot signal composition is seriously weakened in by channel, only with regard to using low pass filter, have the problem of the performance degradation of the carrier wave demodulation system that is difficult to stop the frequency of utilization phased lock loop.
Fig. 6 a～Fig. 6 c is used for the schematic diagram that the characteristic to the synthetic synergistic device output signal of carrier restoring unit describes.
Fig. 6 a shows is to be received under the situation that device stably receives the frequency spectrum of the I signal that forms in the base band in pilot signal.What Fig. 6 b and Fig. 6 c showed is under the situation that pilot signal is seriously weakened by channel, the spectral characteristic of baseband signal.
Under the situation that carrier restoring fails ideally to realize, pilot signal also has frequency pilot to a certain degree, is positioned near the DC simultaneously.
Thereby, under the situation that pilot signal is damaged by channel, the output of the I signal of synthetic synergistic device, its power is a little less than becoming very near the DC.
On the other hand, as previously mentioned, along with being that carry out under the situation that carrier wave demodulation dies down on the basis with the pilot signal, there is the problem that finally can't carry out carrier wave demodulation because of its performance degradation smoothly in the size of pilot signal in the Frequency Phase Lock loop algorithm.
Summary of the invention
The present invention designs for addressing the above problem just, its purpose is: be provided at reception with demodulation of residual sideband mode and the signal that transmits and go back under the situation of primary carrier, when dying down, can make big or small certain vestigial sideband reception machine of this pilot signal by the pilot signal composition that transmits channel.
According to the vestigial sideband reception machine that is intended to realize that above-mentioned purpose the present invention designs, with regard to the receiver of Digital Television that the passband analog signal that will be received is demodulated to baseband digital signal, comprise: in the frequency of wanting channel by day line options and after intermediate frequency is changed, the certain bandwidth that only makes above-mentioned intermediate frequency by and carry out digitized digital processing element; To compare through the performance number of removing the output signal of the low pass filter of unwanted signal when going back primary carrier in the digitized passband signal and set standard value or critical value, according to comparative result, will be adjusted to the carrier restoring unit of size of wanting and the carrier wave that reduces base band through the pilot component in the digitized passband signal; In baseband signal, remove pilot signal and extract the synchronous demodulation unit of synchronizing signal; Utilize synchronizing signal to remove the linear noise of baseband signal and the noise removal unit of residual phase noise; To the decoding unit of decoding through the baseband signal of noise removal.
On the one hand, above-mentioned synchronous demodulation unit comprises that the DC remover of removing pilot signal and the synchronous unit of extracting synchronizing signal in the signal of having removed pilot signal constitute, the noise removal unit is by the channel equalizer of removing linear noise in the signal of having removed pilot signal and removed the phase tracking device of removing the residual phase noise in the signal of linear noise and constitute, and decoding unit is made of the FEC unit of decoding to transmitting at the signal of having removed the residual phase noise.
And, be intended to realize also comprise the carrier redactor of the present invention of above-mentioned purpose: will multiply each other the synthetic synergistic device that the carrier wave of baseband signal is reduced and exports from the frequency of oscillation of frequency phased lock loop and passband signal through digital translation; Utilize the pilot signal of baseband signal to make the frequency and the phase locking of baseband signal, the Frequency Phase Lock loop that frequency of oscillation is generated; The power of baseband signal value of incoming frequency phased lock loop and set standard value or critical value are compared, and included pilot signal is adjusted to size of wanting and the gain control of exporting to the Frequency Phase Lock loop in the baseband signal that will export from synthetic synergistic device.
Moreover above-mentioned gain control comprises: behind the signal of having removed carrier restoring institute unnecessary data composition from the baseband signal of incoming frequency phased lock loop, calculate the power calculation unit of the power of baseband signal of synthetic synergistic device; The comparing unit that as calculated performance number and set standard value or critical value are compared and export; Be arranged between synthetic synergistic device and the Frequency Phase Lock loop, according to the output result of comparing unit the gain of the baseband signal exported from synthetic synergistic device is controlled, come the size of pilot signal is regulated and exported through going back the synergy regulon of primary carrier.
And, in above-mentioned synthetic synergistic device,, then itself and frequency of oscillation are multiplied each other and synthesize I, the Q signal of base band if the I, the Q signals that have a passband of 90 degree phase differences through the passband signal of digital translation are transfused to; The synergy regulon then is made of the 1st, the 2nd synergy regulon that the synergy separately of the signal of I, the Q of base band is controlled.
And, the said frequencies phased lock loop comprises: be included in and remove the frequency locked loop that the 1st low pass filter, delayer, code extractor, synergistic device, loop filter and the frequency oscillator of locking frequency constitutes after the unnecessary data composition in the I signal of the base band by gain adjustment unit; Be included in the 2nd low pass filter of removing locking phase after the unnecessary data composition in the Q signal of above-mentioned base band, synergistic device, loop filter, and the phased lock loop that constitutes of frequency oscillator.And above-mentioned power calculation unit is calculated the power of the baseband I signal by the 1st low pass filter.
Moreover above-mentioned gain control comprises: behind the signal of from the baseband signal of incoming frequency phased lock loop, having removed carrier restoring institute unnecessary data composition, and the power calculation unit that the power of the signal of synthetic synergistic device is calculated; The comparing unit that the performance number calculated and set standard value or critical value are compared and export; Be arranged between the frequency and phase error detection unit and loop filter of Frequency Phase Lock loop, size of regulating pilot signal and the gain adjustment unit that exports loop filter to controlled in the gain of output baseband signal from frequency and phase error detection unit according to the output result in the foundation comparing unit.
Another object of the present invention, characteristic and advantage can obtain understanding to the detailed description that embodiment did by the reference accompanying drawing.
The present invention has following effect: make it possible to automatically the gain of Frequency Phase Lock loop loop be regulated under the situation that the size in pilot signal dies down, even under the channel condition that the size of pilot signal dies down, also can more stably carry out carrier restoring.
Description of drawings
Fig. 1 is the structure chart of formation of the emitter of common Digital Television.
Fig. 2 is the structure chart of detailed formation of VSB modulating unit of the emitter of Digital Television shown in Figure 1.
Fig. 3 is the structure chart of formation of the receiving system of common Digital Television.
Fig. 4 is the structure chart of detailed formation of carrier restoring unit of the receiving system of Digital Television shown in Figure 3.
Fig. 5 is the schematic diagram of the S-curve characteristic that forms according to the Phase synchronization loop.
Fig. 6 a～Fig. 6 c is the schematic diagram that is used to illustrate the characteristic of synthesizing the synergistic device output signal.
Fig. 7 is the structure chart of detailed formation of carrier restoring unit of receiving system of the Digital Television of the 1st embodiment of the present invention.
Fig. 8 is the structure chart of detailed formation of carrier restoring unit of receiving system of the Digital Television of the 2nd embodiment of the present invention.
Accompanying drawing major part symbol description
701,801: synthetic 702: the 1 gain adjustment unit of synergistic device
704,802: the 1 low pass filters 705,803: the 2 low pass filters
706,804: delayer 707,805: code extractor
708,806: synergistic device 709,807: power calculation unit
710,810: loop filter 711,811: voltage-controlled oscillator
712,808: comparing unit 720,820: gain control
730,830: the Frequency Phase Lock loop
Embodiment
Below, with reference to accompanying drawing vestigial sideband reception machine of the present invention and carrier redactor are elaborated.
Fig. 7 is the structure chart of detailed formation of carrier restoring unit of receiving system of the Digital Television of the 1st embodiment.
The carrier restoring unit of the receiving system of the Digital Television of the 1st embodiment of the present invention, comprise:, then make its 90 degree be inverted and convert to the Hilbert transducer of exporting after the Q signal of imaginary number character (not shown) if passband (PassBand) analog signal is converted into the digital signal line output of going forward side by side; After the processing time of the Q signal that postpones to be equivalent to be used for digital signal is converted to the Hilbert transducer, the output signal of I, Q output signal and voltage-controlled oscillator 711 in the delayer (not shown) of the I signal of output real number character is multiplied each other and the synthetic I of base band, the synthetic synergistic device 701 of Q signal (carrier wave) exported; With by the 1st low pass filter 704, delayer 706, code extractor 707, synergistic device 708, loop filter 710 and voltage-controlled oscillator (VCO) 711 constitute and frequency locked loop (Frequency Locked Loop) that the frequency of the I signal of base band is locked and by the 2nd low pass filter 705, the Frequency Phase Lock loop 730 that loop filter 710 and voltage-controlled oscillator (VCO) 711 constitute and the phased lock loop (Phase Locked Loop) that the phase place of Q signal locks is constituted; The power calculation unit of calculating by the pilot power of I signal 709 to output from the 1st low pass filter 704, pilot power that calculates in the power calculation unit 709 and the comparing unit 712 that prior critical value that is provided with or standard value compare are synthesized synergistic device 701 and the 1st with being separately positioned on, the 2nd low pass filter 704, between 705, by the I of output result to exporting in the synthetic synergistic device 701 according to foundation comparing unit 712, the gain of Q output signal is regulated size that the size adjustment of the pilot signal that will be used to go back primary carrier becomes to want and to the 1st of Frequency Phase Lock loop 730, the 2nd low pass filter 704,705 export the 1st, the 2nd gain adjustment unit 702,703 gain controls 720 that constitute.
The basic comprising of digital television receiving apparatus of the present invention and digital television receiving apparatus shown in Figure 3 are similar, just with regard to the carrier restoring unit reduces to carrier wave, if in common digital processing element, at the channel frequency of wanting by the sky line options and after converting intermediate frequency to, the certain frequency band that only makes intermediate frequency by and carry out digitlization, then will from passband signal, remove carrier restoring the performance number of output signal of the 1st low pass filter 704 of unnecessary signal and set standard value or critical value compare, the size that will become to want through the size adjustment of the pilot component of digitized passband signal according to comparative result is also reduced to carrier wave.It is removed other pilot signal and extracts the synchronous demodulation unit of synchronizing signal and utilize above-mentioned synchronizing signal to remove the linear noise of baseband signal and the noise removal unit of residual phase noise and the decoding unit that the baseband signal of having removed noise is decoded that (for example: the formation FEC unit) is identical with common formation, so omits detailed description thereof.
As previously mentioned, the Frequency Phase Lock loop algorithm is carried out carrier restoring according to pilot signal.Thereby, using the 1st low pass filter 704 in order to remove carrier restoring institute unnecessary data composition, 709 power to the 1st low pass filter 704 output signals of power calculation unit calculate.
And the 1st, the 2nd gain adjustment unit 702,703 is utilized the performance number that calculates in the power calculation unit 709, and to the 1st, the 2nd low pass filter 704,705 input signals, i.e. the gain (gain) of the I of carrier restoring unit, Q output signal is regulated.
Thereby the degree of the output signal of the 1st, the 2nd low pass filter 704,705 that reduces of can dying down according to the size along with pilot signal is regulated the size of filter input signal.Under the situation of power (power) standardization (normalization) of the input signal that will import the 1st, the 2nd low pass filter 704,705, there is linear noise, therefore even under the situation that the power of pilot signal dies down, also can make pilot signal import the 1st, the 2nd low pass filter 704,705 with certain power.This just means, more than is to enlarge under situation about dying down relatively by the size in pilot signal, even therefore under the situation that pilot signal dies down, also can enlarge the gain of whole Frequency Phase Lock loop.
Fig. 8 is the structure chart of detailed formation of carrier restoring unit of receiving system of the Digital Television of the 2nd embodiment of the present invention.
In the 2nd embodiment of the present invention, comprise:, then make its 90 degree be inverted and convert to the Hilbert transducer of exporting after the Q signal of imaginary number character (not shown) if the passband analog signal is converted into the digital signal line output of going forward side by side; After the processing time of the Q signal that postpones to be equivalent to be used for digital signal is converted to the Hilbert transducer, the delayer (not shown) of the I signal of output real number character; The output signal of I, Q output signal and the voltage-controlled oscillator 811 of above-mentioned delayer and Hilbert transducer multiplied each other and the I of synthetic output base band, the synthetic synergistic device 801 of Q signal (carrier wave); With the frequency locked loop that constitutes by the 1st low pass filter 802, delayer 804, code extractor 805, synergistic device 806, loop filter 810 and voltage-controlled oscillator 811 and the frequency of the I signal of base band is locked (with the Frequency Phase Lock loop 830 that constitutes by the 2nd low pass filter 803, synergistic device 806, loop filter 810 and voltage-controlled oscillator 811 and the phased lock loop that the phase place of the Q signal of base band locks is constituted; By the power calculation unit 807 that the power from the I output signal of the 2nd low pass filter 803 is calculated, the comparing unit 808 that the power of the I output signal that will calculate in power calculation unit 807 and critical value that is provided with in advance or standard value compare and by the output result of output valve that receives above-mentioned synergistic device 806 and comparing unit 808 and to the I of output in the synthetic synergistic device 801, the gain of Q output signal is regulated, in view of the above the gain control 820 that constitutes of size that the size adjustment of pilot signal is become to want and the gain adjustment unit 809 that exports Frequency Phase Lock loop 830 to.
In the 2nd embodiment of the present invention, I, the Q signal of actual outgoing carrier reduction unit from synthetic synergistic device 801.
At this moment, become under 1 the situation in the gain-adjusted of passing through the 1st low pass filter 802, therefore the gain of 805 pairs of signals of code extractor does not produce any influence, and it is equivalent gain adjustment unit 809 being arranged on the embodiment of Fig. 8 of next end of synergistic device 806 and the embodiment of Fig. 7.
In Fig. 8, gain adjustment unit 809 can be interpreted as the gain of synergistic device (error detector) 806 is regulated.
In the Frequency Phase Lock cyclic system, under the situation that pilot signal dies down, the gain of the S-curve of phased lock loop shown in Figure 5 reduces relatively.In the 2nd embodiment of the present invention of Fig. 8, the gain of the error extracted from synergistic device 806 is enlarged, therefore the gain to whole loop is regulated under the situation that pilot signal dies down.
By the above content that is illustrated, the staff in this field can recognize, can carry out numerous variations and correction within the scope that does not break away from technological thought of the present invention.
Thereby, the content that technical scope of the present invention is not limited among the embodiment to be write down, and should determine by the claim scope.
Claims (8)
1, a kind of vestigial sideband reception machine with regard to the receiver of Digital Television that the passband analog signal that will be received is demodulated to baseband digital signal, is characterized in that, comprising:
In the frequency of wanting channel by day line options and after intermediate frequency is changed, the certain bandwidth that only makes above-mentioned intermediate frequency by and carry out digitized digital processing element;
To compare through the performance number of removing the output signal of the low pass filter of unwanted signal when going back primary carrier in the digitized passband signal and set standard value or critical value, according to comparative result, will be adjusted to the carrier restoring unit of size of wanting and the carrier wave that reduces base band through the pilot component in the digitized passband signal;
In baseband signal, remove pilot signal and extract the synchronous demodulation unit of synchronizing signal;
Utilize synchronizing signal to remove the linear noise of baseband signal and the noise removal unit of residual phase noise;
To the decoding unit of decoding through the baseband signal of noise removal.
2, vestigial sideband reception machine as claimed in claim 1 is characterized in that:
The synchronous demodulation unit comprises: remove the DC remover of pilot signal and extract the synchronous unit of synchronizing signal in the signal of having removed pilot signal;
The noise removal unit comprises: remove the channel equalizer of linear noise and removed the phase tracking device of removing the residual phase noise in the signal of linear noise in the signal of having removed pilot signal;
Decoding unit comprises: the FEC unit that the baseband signal of having removed noise is decoded.
3, a kind of carrier redactor is characterized in that, comprising:
To multiply each other the synthetic synergistic device that the carrier wave of baseband signal is reduced and exports from the frequency of oscillation of frequency phased lock loop and passband signal through digital translation;
Utilize the pilot signal of baseband signal to make the frequency and the phase locking of baseband signal, the Frequency Phase Lock loop that frequency of oscillation is generated;
The power of baseband signal value of incoming frequency phased lock loop and set standard value or critical value are compared, and included pilot signal is adjusted to size of wanting and the gain control of exporting to the Frequency Phase Lock loop in the baseband signal that will export from synthetic synergistic device.
4, carrier redactor as claimed in claim 3 is characterized in that, gain control comprises:
From the baseband signal of incoming frequency phased lock loop, removed carrier restoring behind the signal of unnecessary digital composition, calculate the power calculation unit of the baseband signal power of synthetic synergistic device; The comparing unit that as calculated performance number and set standard value or critical value are compared and export;
Be arranged between synthetic synergistic device and the Frequency Phase Lock loop, according to the output result of foundation comparing unit the gain of the baseband signal exported from synthetic synergistic device controlled synergy regulon through the carrier wave of reduction is regulated and exported to the size of pilot signal.
5, carrier redactor as claimed in claim 4 is characterized in that:
In above-mentioned synthetic synergistic device,, then itself and frequency of oscillation are multiplied each other and synthesize I, the Q signal of base band if the I, the Q signals that have a passband of 90 degree phase differences through the passband signal of digital translation are transfused to; The synergy regulon then is made of the 1st, the 2nd synergy regulon that the synergy separately of the signal of I, the Q of base band is controlled.
6, carrier redactor as claimed in claim 4 is characterized in that, the Frequency Phase Lock loop comprises:
By in the I signal of the base band by gain adjustment unit, removing the frequency locked loop that the 1st low pass filter, delayer, code extractor, synergistic device, loop filter and the frequency oscillator of locking frequency constitutes after the unnecessary data composition;
By the 2nd low pass filter of in the Q signal of above-mentioned base band, removing locking phase after the unnecessary data composition, synergistic device, loop filter, and the phased lock loop that constitutes of frequency oscillator.
7, carrier redactor as claimed in claim 6 is characterized in that: above-mentioned power calculation unit is calculated the power of the baseband I signal by the 1st low pass filter.
8, carrier redactor as claimed in claim 3 is characterized in that, above-mentioned gain control comprises:
Behind the signal of from the baseband signal of incoming frequency phased lock loop, having removed carrier restoring institute unnecessary data composition, the power calculation unit that the power of baseband signal of synthetic synergistic device is calculated;
The comparing unit that the performance number calculated and set standard value or critical value are compared and export;
Be arranged between the frequency and phase error detection unit and loop filter of Frequency Phase Lock loop, size of regulating pilot signal and the gain adjustment unit that exports loop filter to controlled in the gain of output baseband signal from frequency and phase error detection unit according to the output result in the comparing unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100845803A CN100499615C (en) | 2004-11-25 | 2004-11-25 | Residual side-band receiver and carrier releaser |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100845803A CN100499615C (en) | 2004-11-25 | 2004-11-25 | Residual side-band receiver and carrier releaser |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1780275A CN1780275A (en) | 2006-05-31 |
| CN100499615C true CN100499615C (en) | 2009-06-10 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2004100845803A Expired - Fee Related CN100499615C (en) | 2004-11-25 | 2004-11-25 | Residual side-band receiver and carrier releaser |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100499615C (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8305492B2 (en) * | 2010-04-13 | 2012-11-06 | Newport Media, Inc. | Dual burst locked oscillator architecture for an analog television receiver |
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2004
- 2004-11-25 CN CNB2004100845803A patent/CN100499615C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN1780275A (en) | 2006-05-31 |
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