CN1463093A - Carrier restoring equipment of digital broadcasting receiver using two pilot signal and its method - Google Patents

Carrier restoring equipment of digital broadcasting receiver using two pilot signal and its method Download PDF

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Publication number
CN1463093A
CN1463093A CN02144350A CN02144350A CN1463093A CN 1463093 A CN1463093 A CN 1463093A CN 02144350 A CN02144350 A CN 02144350A CN 02144350 A CN02144350 A CN 02144350A CN 1463093 A CN1463093 A CN 1463093A
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frequency
carrier
signal
unit
lpf
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CN02144350A
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CN1206840C (en
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金俊守
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Samsung Electronics Co Ltd
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Samsung Electronics Co Ltd
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N7/00—Television systems
    • H04N7/08—Systems for the simultaneous or sequential transmission of more than one television signal, e.g. additional information signals, the signals occupying wholly or partially the same frequency band, e.g. by time division
    • H04N7/087—Systems for the simultaneous or sequential transmission of more than one television signal, e.g. additional information signals, the signals occupying wholly or partially the same frequency band, e.g. by time division with signal insertion during the vertical blanking interval only
    • H04N7/088—Systems for the simultaneous or sequential transmission of more than one television signal, e.g. additional information signals, the signals occupying wholly or partially the same frequency band, e.g. by time division with signal insertion during the vertical blanking interval only the inserted signal being digital
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N7/00—Television systems
    • H04N7/015—High-definition television systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N7/00—Television systems
    • H04N7/025—Systems for the transmission of digital non-picture data, e.g. of text during the active part of a television frame
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N7/00—Television systems
    • H04N7/06—Systems for the simultaneous transmission of one television signal, i.e. both picture and sound, by more than one carrier
    • H04N7/066—Systems for the simultaneous transmission of one television signal, i.e. both picture and sound, by more than one carrier the carriers being allocated to more than one television channel

Abstract

A carrier restoring system of a digital broadcasting receiver is provided and the method thereof. A carrier restoring system of a digital broadcasting receiver includes a plurality of frequency offset assumption units, a combining unit, a phase offset assumption unit, and a voltage-controlled oscillator. Each of the plurality of frequency offset assumption unit shifts a plurality of pilot tones included in I-signal and Q-signal of a digital broadcasting signal to a baseband to assume a frequency offset value of a carrier, generated when the digital broadcasting signal is tuned. The combining unit combines frequency offset values assumed by the plurality of frequency offset assumption units. The phase offset assumption unit assumes a phase offset value of the carrier. The voltage-controlled oscillator compensates for the frequency offset value and the phase offset value to oscillate a voltage with a predetermined level for carrying out tuning.

Description

Carrier restorer and method with the digit broadcasting receiver of two pilot signals
Technical field
The present invention relates generally to the equipment and the method that are used for the reinsertion of carrier on the receiver of digit broadcasting system, relate in particular to and to recover by in the process of residual sideband (VSB) modulated digital broadcast singal, according to the pilot tone that is included in the pilot tone in the broadcast singal, compensate the frequency shift (FS) of the carrier wave that occurs in stand-by period and the equipment and the method for phase deviation.
Background technology
Usually, the broadcast singal transmitting system comprises residual sideband (VSB) modulation and coded orthogonal frequency division multiplexing (COFDM) modulation.The VSB modulation sends the broadcast singal on the single carrier.The COFDM modulation sends broadcast singal through the frequency division multiplex of broadcast singal by multichannel.The VSB modulation is the digit broadcasting system that the U.S. advocates, and adopts in the country such as the Korea S and the U.S..The COFDM modulation is the digit broadcasting system that advocate in Europe.
Fig. 1 is the VSB receiver block diagram that illustrates as the example of conventional digit broadcasting receiver.The VSB receiver comprises tuner 12, surface acoustic wave (SAW) filter 14, intermediate frequency (IF) amplifying unit 16, analog-digital converter (ADC) 18, I/Q separator 20, matched filter 22, pilot tone removal unit 24, downsampling unit 26 and balanced unit 28.
Tuner 12 according to the tune command digital broadcast signal that will on antenna 10, receive of input be tuned to frequency band corresponding.SAW filter 14 is with the digital broadcast signal filtering of tuning frequency band to the intermediate frequency that presets (IF).Intermediate frequency (IF) amplifying unit 16 will be amplified to intermediate frequency (IF) from the digital broadcast signal that the intermediate frequency (IF) of SAW filter 14 outputs is with.ADC 18 is converted to digital signal with the digital broadcast signal that intermediate frequency (IF) amplifies.I/Q separator 20 is separated into in-phase channel signal (being called the I-signal hereinafter) and orthogonal signalling (being called the Q-signal hereinafter) with digital broadcast signal.Matched filter 22 with I and Q signal filtering so that it has received sinusoidal feature when sending.Pilot tone is removed unit 24 and remove pilot tone from the I of filtering and Q signal.Downsampling unit 26 reduces (pilot-removed) I of pilot tone removal and the size of Q signal according to preset value.The I of the down-sampling that balanced unit 28 compensation have occurred in transmission and the distortion of Q signal.
Simultaneously, conventional VSB receiver comprises sampling compensating unit 30 and the frequency/phase lock unit 40 that is used for compensating offset, and described skew occurred between the convalescence of the digital broadcast signal that receives.The timing distortion that 30 compensation of sampling compensating unit have occurred between the sampling period of ADC 18.Skew of frequency/phase lock unit 40 compensating frequencies and phase deviation, described frequency shift (FS) and phase deviation occur at the stand-by period of tuner 12.
Fig. 2 is the block diagram that illustrates in greater detail the frequency/phase lock unit 40 of Fig. 1.Frequency/phase lock unit 40 comprises first low pass filter (LPF) 42, automatic frequency control low pass filter (AFC-LPF) 44, amplitude limiter 46, the 2nd LPF 48, multiplier 50, automatic phased low pass filter (APC-LPF) 52 and voltage controlled oscillator (VCO) 54.
The pilot tone of the I-signal in the one LPF 42 filtered baseband.AFC-LPF 44 calculates the difference on the frequency of the pilot tone that is used for the I-signal.Amplitude limiter 46 produces the impulse wave corresponding to the difference of the pilot tone of exporting from AFC-LPF 44.The 2nd LPF 48 filtering are used for the pilot tone of the Q-signal of base band.The impulse wave that multiplier 50 usefulness are exported from amplitude limiter 46 from the Q-signal times of the 2nd LPF 48 outputs.APC-LPF 52 calculates the phase difference of the pilot tone that is used for the Q-signal.VCO 54 offers tuner 12 with preset level, the difference on the frequency of tuning thus compensation pilot tone and phase difference.
Conventional digit broadcasting receiver estimates to be used for the frequency shift (FS) and the phase deviation of subcarrier through I and Q signal, and the skew of compensate for estimated, and it is tuning to be used for that the level voltage that presets is offered tuner 12.Therefore, can compensate the frequency shift (FS) and the phase deviation of the carrier wave that occurs at the stand-by period of tuner 12.
The carrier recovering method of the conventional frequency/phase lock unit 40 of this use uses a pilot tone for each signal.Therefore, if pilot tone is destroyed, the carrier wave on conventional digit broadcasting receiver recovers quality meeting severe exacerbation so.Usually, the surface wave transmitting channel can be modulated to multipath channel, and in the case, the frequency response of channel comprises a lot of null values.Even only one of null value is present in the frequency band identical with pilot tone, the pilot tone of digital broadcast signal also can be by heavy damage.When this takes place, can not expect the accurate recovery of carrier wave.
Summary of the invention
Therefore, an object of the present invention is to provide the carrier restorer and the method thereof that are used for digit broadcasting receiver, can consider under the ruined situation of pilot tone, more easily recover the carrier wave of the digital broadcast signal of reception.
Another object of the present invention provides the carrier restorer and the method thereof of digit broadcasting receiver, even can be when pilot tone be destroyed, and the reinsertion of carrier easily still.
According to the present invention, provide a kind of carrier restorer of digit broadcasting receiver.This carrier restorer utilization is included in I signal and the Q signal in the digital broadcast signal, recovery is in the skew of the carrier wave of stand-by period appearance, this equipment comprises: a plurality of Frequency offset estimation unit, be used for moving on to base band respectively the frequency shift (FS) of the carrier wave that estimation occurs during tuning digital broadcast signal by a plurality of pilot tones that will be included in I signal and Q signal; Assembled unit is used to make up the frequency shift (FS) by a plurality of Frequency offset estimation unit estimation; The phase deviation estimation unit is used to estimate made up the phase deviation of the carrier wave of frequency shift (FS) by assembled unit for it; And voltage controlled oscillator (VCO) unit, the preset level voltage that is used to vibrate is used for compensating frequency skew and phase deviation, and tuning subsequently.
According to the present invention, provide a kind of carrier recovering method that is used for the carrier restorer of digit broadcasting receiver.The carrier recovering method utilization is included in I signal and the Q signal in the digital broadcast signal, recovery is in the skew of the carrier wave of stand-by period appearance, this method may further comprise the steps: be included in a plurality of pilot tones in I-signal and the Q-signal by utilization, estimate the frequency shift (FS) of the carrier wave that occurs at stand-by period; Combination is according to a plurality of pilot tone estimated frequency shift; Utilize the phase deviation of the combined value estimation carrier wave of frequency shift (FS); And vibration preset level voltage, be used to compensate the frequency shift (FS) and the phase deviation that are used for tuning carrier wave.
Description of drawings
By describing the preferred embodiments of the present invention with reference to the accompanying drawings, it is clearer that above-mentioned purpose of the present invention and characteristics will become, wherein:
Fig. 1 is the block diagram of conventional digit broadcasting receiver;
Fig. 2 is the block diagram of the frequency/phase lock unit of more detailed Fig. 1;
Fig. 3 is the block diagram of digit broadcasting receiver and carrier restorer according to the preferred embodiment of the invention;
Fig. 4 is the block diagram that illustrates in greater detail the first and second Frequency offset estimation unit among Fig. 3;
Fig. 5 A is the figure that illustrates in greater detail first frequency shift unit of Fig. 4;
Fig. 5 B is the figure that illustrates in greater detail second frequency shift unit of Fig. 4;
Fig. 6 is the block diagram that illustrates in greater detail the phase deviation estimation unit of Fig. 3;
Fig. 7 illustrates to be used to utilize the flow chart of the method for the carrier restorer reinsertion of carrier of digit broadcasting receiver according to the preferred embodiment of the invention;
Fig. 8 is the flow chart that the Frequency offset estimation step of detailed Fig. 7 is shown;
Fig. 9 is the flow chart that the frequency displacement step of detailed Fig. 8 is shown;
Figure 10 is the flow chart that the phase deviation estimating step of detailed Fig. 7 is shown.
Embodiment
Hereinafter, more detailed description the preferred embodiments of the present invention with reference to the accompanying drawings.
Fig. 3 is according to the carrier restorer of digital broadcast signal of the present invention and the block diagram of digit broadcasting receiver.Digit broadcasting receiver comprises tuner 62, surface acoustic wave (SAW) filter 64, intermediate frequency (IF) amplifying unit 66, analog-digital converter (ADC) 68, I/Q separator 70, matched filter 72, pilot tone removal unit 74, downsampling unit 76, balanced unit 78, sampling compensating unit 80 and carrier restorer 100.
Tuner 62 according to tune command with the digital broadcast signal that receives on the antenna 60 be tuned to frequency band corresponding.SAW filter 64 is with the digital broadcast signal filtering of tuning frequency band to the intermediate frequency that presets (IF).Intermediate frequency (IF) amplifying unit 66 will be amplified to intermediate frequency from the digital broadcast signal intermediate frequency (IF) band of SAW filter 64 outputs.ADC 68 is converted to digital signal with the digital broadcast signal that intermediate frequency amplifies.I/Q separator 70 is separated into I and Q signal respectively with digital broadcast signal.72 couples of I of matched filter and Q signal filtering are so that it has the sinusoidal feature of accepting when sending.Pilot tone is removed unit 74 and remove pilot tone from the I of filtering and Q signal.Downsampling unit 76 reduces the I of pilot tone removal and the size of Q signal.The down-sampling I that balanced unit 78 compensation have occurred during sending and the distortion of Q signal.
The timing distortion that 80 compensation of sampling compensating unit have occurred between the sampling period of ADC 68.Carrier restorer 100 is included in the pilot tone in the symbol of digital broadcast signal by use, frequency shift (FS) and phase deviation that compensation occurs at the stand-by period of tuner 62.In this embodiment, by using frequency shift (FS) and phase deviation about two (2) pilot tone reinsertions of carrier of a symbol.
As shown in the figure, carrier restorer 100 comprises first frequency skew estimation unit 120, second frequency skew estimation unit 140, assembled unit 160, phase deviation estimation unit 170 and voltage controlled oscillator (VCO) 180.
The frequency shift (FS) that first frequency skew estimation unit 120 is estimated carrier wave by the I and the Q signal of use first pilot tone.The frequency shift (FS) that second frequency skew estimation unit 140 is estimated carrier wave by the I and the Q signal of use second pilot tone.The frequency shift (FS) that assembled unit 160 combinations are estimated respectively by the first and second Frequency offset estimation unit 120,140 about carrier wave.Phase deviation estimation unit 170 is estimated the phase deviation of carrier wave according to the combined value of each frequency shift (FS) on the assembled unit 160.VCO 180 provides preset level for tuner 62, thus the frequency shift (FS) and the phase deviation of compensation and tuning carrier wave.
Based on carrier estimation frequency shift (FS), and estimate to reduce the phase deviation of carrier wave because the error probability of the carrier wave recovery that the pilot tone of damaging produces by the combination estimated value about two pilot tones of a symbol.Therefore, the reinsertion of carrier more easily.
Fig. 4 is the block diagram that illustrates in greater detail the first and second Frequency offset estimation unit 120,140 among Fig. 3.
First frequency skew estimation unit 120 comprises first frequency shift unit 121, first low pass filter (LPF) 123, first automatic frequency control low pass filter (AFC-LPF) 125, first amplitude limiter 127 and first multiplier 129.
First frequency shift unit 121 moves from the I of I/Q separator 121 output and first pilot tone in two pilot tones the Q signal to base band.The one LPF 123 filtering are from the frequency band of first pilot tone of first frequency shift unit, 121 outputs.The one AFC-LPF 125 is with the band filter of first pilot tone, to calculate the difference on the frequency of the predetermined reference signal and first pilot tone.First amplitude limiter 127 produces the impulse wave corresponding to the frequency offseting value of carrier wave according to the difference on the frequency that calculates from an AFC-LPF125.First multiplier, 129 usefulness have the Q-signal in first pilot tone of a LPF 123 filtering, take advantage of the impulse wave that produces from first amplitude limiter 127.
More particularly, be on the occasion of one of, negative value and 0 from the difference on the frequency of an AFC-LPF 125 output.For example, when the difference on the frequency from AFC-LPF 125 output is timing, first amplitude limiter 127 produces+1 impulse wave; When from the difference on the frequency of AFC-LPF output when negative, produce-1 impulse wave; And when the difference on the frequency from AFC-LPF output is 0, produce 0 impulse wave.
Second frequency skew estimation unit 140 comprises the 2nd LPF 143, the 2nd AFC-LPF 145, second amplitude limiter 147 and second multiplication unit 149.Second frequency skew estimation unit 140 utilizes and is included in from the I of I/Q separator 70 outputs and second pilot tone in two pilot tones the Q signal, carries out the identical processing of being done with first frequency skew estimation unit 120.
More particularly, be on the occasion of one of, negative value and 0 from the difference on the frequency of the 2nd AFC-LPF 145 output.For example, when the difference on the frequency from AFC-LPF 145 output is timing, second amplitude limiter 147 produces+1 impulse wave; When from the difference on the frequency of AFC-LPF output when negative, produce-1 impulse wave; And when the difference on the frequency from AFC-LPF output is 0, produce 0 impulse wave.
Assembled unit 160 combination is from the result of first and second multiplication units, 129, the 149 outputs combined value with the frequency shift (FS) of calculating carrier wave.
Fig. 5 A is the figure that illustrates in greater detail first frequency shift unit 121 of Fig. 4, and Fig. 5 B is the figure that illustrates in greater detail second frequency shift unit 141 of Fig. 4.First frequency shift unit 121 comprises first digital controlled oscillator (NCO) 121a and the first complex multiplication unit 121b.The one NCO 121a calculates the frequency values that is used for first pilot tone of I and Q signal is moved on to base band.First complex multiplication unit 121b I and the Q signal of being exported from I/Q separator 70 by the frequency values CM of NCO 121a calculating is to move on to base band with first pilot tone.Second frequency shift unit 141 comprises second digital controlled oscillator (NCO) 141a and the second complex multiplication unit 141b.The 2nd NCO 141a calculates the frequency values that is used for second pilot tone of I and Q signal is moved on to base band.Second complex multiplication unit 141b frequency values CM I and the Q signal that is calculated by the 2nd NCO 141a is to move on to base band with second pilot tone.
For example, the frequency values from a NCO 121a and the 2nd NCO 141a output be respectively-3.57MHz and+3.57MHz.
Fig. 6 is the block diagram that illustrates in greater detail the phase deviation estimation unit 170 of Fig. 3.Phase deviation estimation unit 170 comprises loop filter 172 and APC-LPF 174.Loop filter 172 filtering come from the combined value of assembled unit 160, so that combined value can keep sinusoidal model.APC-LPF 174 estimates the phase pushing figure of carrier wave by calculating from the combined value of loop filter 172 outputs and the phase difference of predetermined reference signal.
VCO 180 vibration preset level voltages are used to compensate by the frequency shift (FS) of assembled unit 160 combinations and the phase deviation of being estimated by phase deviation estimation unit 170, and provide preset level voltage for tuner 62.
According to a preferred embodiment of the invention, based on the frequency shift (FS) and the phase deviation of the carrier wave that utilizes two pilot tones to estimate, the digit broadcasting receiver reinsertion of carrier.Therefore, even when pilot tone is destroyed, the reinsertion of carrier easily still.
Fig. 7 illustrates to utilize the flow chart of the carrier recovering method of the carrier restorer of digit broadcasting receiver according to the preferred embodiment of the invention.At first, first frequency skew estimation unit 120 and second frequency skew estimation unit 140 utilize two pilot tones that are included in I and the Q signal, the frequency shift (FS) of the carrier wave of estimative figure broadcast singal (step S100).Assembled unit 160 combinations are by the first and second Frequency offset estimation unit, 120,140 estimated frequency shift (step S200).Phase deviation estimation unit 170 calculates I and Q signal and the phase difference that presets between the reference signal according to the combined value of assembled unit 160, and according to the phase deviation (step S300) of this result of calculation estimation carrier wave.VCO 180 vibration preset level are used to compensate in the frequency shift (FS) of the carrier wave of combination on the assembled unit 160 and the phase deviation of estimating on phase deviation estimation unit 170, and provide preset level (step S400) for tuner 62.
Because by using two pilot tone reinsertions of carrier with estimated frequency skew and phase deviation, even when digital broadcast signal being sent to the dynamic channel that changes according to the time, carrier wave also can easily recover.
Fig. 8 is the flow chart that illustrates in greater detail the Frequency offset estimation step S100 of Fig. 7.At first, the first and second Frequency offset estimation unit 120,140 move on to base band (step S110) with first and second pilot tones of two pilot tones.By moving on to base band from the I of first and second frequency shift unit, 121,141 outputs and first and second pilot tones the Q signal, first and second LPF 123,143 carry out low-pass filtering (step S120).First and second AFC-LPF, 125,145 filtering are through the frequency band of first and second pilot tones of first and second LPF 123,143 transmission, to calculate first and second pilot tones and to preset difference on the frequency (step S130) between the reference signal.First and second amplitude limiters 127,147 produce the impulse wave (step S140) corresponding to the frequency offseting value of carrier wave respectively according to the difference on the frequency from first and second AFC-LPF, 125,145 outputs.
For example, the difference on the frequency that produces in step S130 is on the occasion of one of, negative value and 0.Therefore, in step S140,, produce+1 impulse wave when the difference on the frequency from AFC-LPF output is timing; When from the difference on the frequency of AFC-LPF output when negative, produce-1 impulse wave; And when the difference on the frequency from AFC-LPF output is 0, produce 0 impulse wave.
First and second multiplication units, 129,149 usefulness are from the corresponding impulse wave that first and second amplitude limiters 127,147 produce, and take advantage of the Q signal (step S150) that comprises from the pilot tone of first and second filtering of first and second LPF 123,143.Therefore, first and second multiplication units 129,149 offer assembled unit 160 (step S160) with multiplied result.
Fig. 9 is the flow chart that illustrates in greater detail the frequency displacement step S110 of Fig. 8.At first, the first and second NCO 121a and 141a calculate the frequency values (step S112) that is used for the pilot tone of I and Q signal is moved on to base band.Therefore, the first and second complex multiplication unit 121b, 141b are according to the multiplication (step S114) of being carried out I and Q signal by the first and second NCO 121a and 141a result calculated.Therefore, the carrier wave of mobile digital broadcast signal.
For example, the frequency values that produces at step S112 be respectively-3.57MHz and+3.57MHz.
Figure 10 is the flow chart that illustrates in greater detail the phase deviation estimating step S300 of Fig. 7.At first, loop filter 172 filtering come from the combined value of assembled unit 160, so that combined value can keep sinusoidal feature (step S320).Phase difference between the combined value of APC-LPF 174 compute low pass filtered and the reference signal that presets is to estimate the phase deviation (step S340) of carrier wave.
Therefore, VCO 180 vibration preset level are used to compensate from the frequency shift (FS) of assembled unit 160 and the phase deviation of being estimated by phase deviation estimation unit 170, and provide preset level voltage for tuner 62.By utilizing two pilot tones to estimate the frequency shift (FS) and the phase deviation of carrier waves, and when the reinsertion of carrier, consider the skew of this estimation, therefore, even when pilot tone is destroyed, the reinsertion of carrier easily still.
According to the present invention, owing to utilize two pilot tones to estimate and the frequency shift (FS) and the phase deviations of the reinsertion of carrier, even when because channel circumstance difference pilot tones when destroyed, the reinsertion of carrier easily still.
Further, owing to utilize two the pilot tone reinsertions of carrier, the reinsertions of carrier exactly.
Although described the preferred embodiments of the present invention, it will be understood to those of skill in the art that the present invention will be not limited to preferred embodiment, and within defined the spirit and scope of the invention, can make different changes and adjustment by claims.

Claims (18)

1. the carrier restorer of a digit broadcasting receiver is used for utilizing the I signal and the Q signal that are included in digital broadcast signal, recovers the skew at the carrier wave of stand-by period generation, and this equipment comprises:
A plurality of Frequency offset estimation unit is used for moving on to base band respectively by a plurality of pilot tones that will be included in I signal and Q signal, the frequency shift (FS) of the carrier wave that estimation occurs during tuning digital broadcast signal;
Assembled unit is used to make up the frequency shift (FS) by a plurality of Frequency offset estimation unit estimation;
The phase deviation estimation unit is used to estimate made up the phase deviation of the carrier wave of frequency shift (FS) by assembled unit for it; And
Voltage controlled oscillator (VCO) unit, the preset level voltage that is used to vibrate is used for compensating frequency skew and phase deviation, and tuning subsequently.
2. carrier restorer as claimed in claim 1, wherein, each of Frequency offset estimation unit all comprises:
Frequency shift unit is used for respectively a plurality of pilot tones being moved on to base band;
Automatic frequency control low pass filter (AFC-LPF) is used for the frequency band by the filtering pilot tone, calculates the difference on the frequency of a plurality of pilot tones respectively;
Amplitude limiter is used for according to the impulse wave of difference on the frequency generation corresponding to the difference on the frequency of carrier wave; And
Multiplication unit is used for comprising the Q-signal times impulse wave of a plurality of mobile pilot tones, wherein
Assembled unit calculates the combined value of a plurality of pilot tones by the combination multiplied result.
3. carrier restorer as claimed in claim 2, wherein, low-pass filtering (LPF) unit that provides between frequency shift unit and the AFC-LPF also is provided each of Frequency offset estimation unit, be used for filtering and export the frequency band of a plurality of pilot tones, use from the impulse wave of amplitude limiter output by multiplication unit at this and take advantage of Q-signal by LPF filtering from frequency shift unit.
4. carrier restorer as claimed in claim 3, wherein, each of frequency shift unit comprises:
Digital controlled oscillator (NCO) is used to calculate the frequency values that is used for a plurality of pilot tones are moved on to base band; And
The complex multiplication unit is used for by with I-signal and Q-signal CM frequency values a plurality of pilot tones being moved on to base band.
5. carrier restorer as claimed in claim 4, wherein, the phase deviation estimation unit comprises:
The loop filtering unit is used for the combined value that filtering comes from assembled unit, so that combined value can keep smoothed curve; And
Automatic phased low pass filter (APC-LPF) is used for the phase deviation of the combined value estimation carrier wave through coming from the loop filtering unit.
6. carrier restorer as claimed in claim 5, wherein, a plurality of pilot tones that are included in I-signal and the Q-signal are two, and two frequency shift unit, LPF, AFC-LPF, amplitude limiter and multiplication units correspondingly are provided respectively.
7. carrier restorer as claimed in claim 6, wherein, from the frequency values of each output of NCO be respectively-3.57MHz and+3.57MHz.
8. carrier restorer as claimed in claim 7 wherein, is on the occasion of one of, negative value and 0 from the difference on the frequency of each output of AFC-LPF.
9. carrier restorer as claimed in claim 8, wherein, when the difference on the frequency from AFC-LPF output is timing, each generation of amplitude limiter+1 impulse wave; When from the difference on the frequency of AFC-LPF output when negative, produce-1 impulse wave; And when the difference on the frequency from AFC-LPF output is 0, produce 0 impulse wave.
10. a carrier recovering method that uses the carrier restorer of digit broadcasting receiver is used for utilizing the I-signal and the Q-signal that are included in digital broadcast signal, recovers the skew at the carrier wave of stand-by period appearance, and this method may further comprise the steps:
Be included in a plurality of pilot tones in I-signal and the Q-signal by utilization, estimate the frequency shift (FS) of the carrier wave that occurs at stand-by period;
Combination is according to a plurality of pilot tone estimated frequency shift;
Utilize the phase deviation of the combined value estimation carrier wave of frequency shift (FS); And
Vibration preset level voltage is used to compensate the frequency shift (FS) and the phase deviation that are used for tuning carrier wave.
11. as the carrier recovering method of claim 10, wherein, may further comprise the steps of Frequency offset estimation step:
Respectively a plurality of pilot tones are moved on to base band;
Be moved to the frequency band of a plurality of pilot tones of base band by filtering, calculate the difference on the frequency of a plurality of pilot tones;
According to the impulse wave of difference on the frequency generation corresponding to the frequency shift (FS) of carrier wave; And
With the Q-signal times impulse wave that comprises a plurality of pilot tones that move on to base band, wherein,
Combination step is calculated the combined value of a plurality of pilot tones by making up each multiplied result.
12. as the carrier recovering method of claim 11, wherein, the Frequency offset estimation step also comprises the low-pass filtering step, is used for the residing arrowband of the wherein a plurality of mobile pilot tones of filtering, wherein,
The multiplication step is taken advantage of filtered Q-signal with impulse wave.
13. as the carrier recovering method of claim 12, wherein, the frequency displacement step may further comprise the steps:
Calculate the frequency values that is used for a plurality of pilot tones are moved on to base band respectively; And
By with I-signal and Q-signal CM frequency values, base band is arrived in a plurality of pilot tone frequency displacements.
14. as the carrier recovering method of claim 13, wherein, the phase deviation estimating step may further comprise the steps:
The loop filtering combined value is so that combined value can keep smoothed curve; And
Estimate the phase pushing figure of carrier wave according to the combined value of loop filtering.
15. as the carrier recovering method of claim 14, wherein, a plurality of pilot tones that are included in I-signal and the Q-signal are two.
16. as the carrier recovering method of claim 14, wherein, from the frequency values of frequency values calculation procedure output be respectively-3.57MHz and+3.57MHz.
17., wherein, be on the occasion of one of, negative value and 0 from the difference on the frequency of difference on the frequency calculation procedure output as the carrier recovering method of claim 16.
18. as the carrier recovering method of claim 17, wherein, when the difference on the frequency from AFC-LPF output is timing, impulse wave produces step and produces+1 impulse wave; When from the difference on the frequency of AFC-LPF output when negative, produce-1 impulse wave; And when the difference on the frequency from AFC-LPF output is 0, produce 0 impulse wave.
CNB021443505A 2002-05-30 2002-10-10 Carrier restoring equipment of digital broadcasting receiver using two pilot signal and its method Expired - Fee Related CN1206840C (en)

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KR1020020030390A KR100859868B1 (en) 2002-05-30 2002-05-30 Carrier Recovery Apparatus of digital broadcasting receiver using the 2 pilot signal

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CN1206840C CN1206840C (en) 2005-06-15

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Publication number Priority date Publication date Assignee Title
CN1333533C (en) * 2005-05-16 2007-08-22 北京北方烽火科技有限公司 Method of frequency compensation for Direct Sequence Spread Spectrum (DSSS) mobile communication system
CN100364302C (en) * 2005-01-28 2008-01-23 北京北广科数字广播电视技术有限公司 Digital audio frequency processing method for analog amplitude modulation medium wave broadcasting transmitter digital improvement

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KR100653181B1 (en) 2005-12-07 2006-12-05 한국전자통신연구원 Non-coherent synchronous direct conversion receive transmit system for estimating frequency offset

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CN100364302C (en) * 2005-01-28 2008-01-23 北京北广科数字广播电视技术有限公司 Digital audio frequency processing method for analog amplitude modulation medium wave broadcasting transmitter digital improvement
CN1333533C (en) * 2005-05-16 2007-08-22 北京北方烽火科技有限公司 Method of frequency compensation for Direct Sequence Spread Spectrum (DSSS) mobile communication system

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