JP2006229671A - Receiver, receiving method, and integrated circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To save on power consumption by shortening a synchronization pull-in time concerning the synchronization technique of a time division receiver. <P>SOLUTION: The receiver for receiving a digital signal and demodulating it comprises: a demodulating part for orthogonally demodulating the received digital signal, on the basis of a signal to be outputted from an oscillating part; a frequency difference detecting part for detecting a difference between the oscillation frequency of the oscillating part and the carrier wave frequency of the digital signal from the output of the orthogonal demodulation part; a control part for controlling the oscillation frequency of the oscillating part, on the basis of the output of the frequency difference detecting part; an estimating part for estimating the oscillation frequency of the oscillating part at a time for supplying power sources again (a second time) from the output of the control part in a plurality of times before turning off a part of or the whole power sources in the receiver (the first times); and a control part for controlling the oscillating part, on the basis of the oscillation frequency which is estimated at the time for supplying the power sources again (the second time). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a receiving apparatus that receives digital broadcasting, and synchronization control of the receiving apparatus.

  In recent years, a DVB-H (Digital Video Broadcast-Handheld) system has been studied as a transmission standard for the terrestrial digital broadcasting mobile terminal in contrast to the terrestrial digital broadcast DVB-T (Digital Video Broadcast-Terrestrial) system in Europe. This method employs the OFDM transmission method, and transmits the program data of the same channel in a time division manner. At this time, each program occupies a bandwidth of about 7 MHz and is transmitted in bursts. In the receiving device, only a signal of a desired channel is received from the digital broadcast radio wave. During the time when the signal of the desired channel is not transmitted, it is considered to reduce power consumption by turning off the power of the demodulator. This method is called time slicing.

  In order to demodulate the digital broadcast signal, it is necessary to reproduce the sampling frequency and the center frequency of the carrier wave. The reproduced state is called a synchronization establishment state. The time required to establish the frequency synchronization state is called the pull-in time, and the pull-in time becomes longer as the deviation between the reference frequency and the scan start frequency increases.

  The receiver cannot demodulate the broadcast signal until synchronization is established, and the viewer cannot view the broadcast.

  Furthermore, as in the DVB-H system, when the demodulator is turned on / off in time division and only the desired signal is received, the synchronization of the received signal must be established for each burst. At this time, the receiving apparatus needs to turn on the power of the demodulator earlier than the time when the desired signal is received by the expected pull-in time. At this time, if a long time is taken as the pull-in time, the period during which the power of the demodulator is turned on becomes longer. The longer the period during which the demodulator is turned on, the more power is consumed.

  Thus, shortening the pull-in time when receiving digital broadcast is an important issue for realizing low power consumption in the DVB-H system.

  As a conventional method for shortening the pull-in time, for example, there is one disclosed in Patent Document 1. FIG. 2 shows a flowchart relating to frequency synchronization disclosed in Patent Document 1. In the conventional embodiment, when the user using the receiving apparatus turns off the power of the apparatus in step 10, the value of the data lock frequency synchronized with the digital broadcast wave received so far is stored in the memory or register. And so on. When the digital broadcast radio wave to be received is received in the past when the power is turned on again, the value of the data lock frequency at the previous reception is known, and the value is stored. In step 11, this data is read as a reference value of the data lock frequency for the digital broadcast to be received. As a result, there is a high possibility that the data lock frequency required at the time of reception this time exists in the band block to which the stored data lock frequency belongs at the time of reception this time, and data from the band block that takes into account the frequency deviation amount in advance. The search for the lock frequency can be started.

  Furthermore, in patent document 1, the frequency deviation resulting from the temperature change of an electronic component is correct | amended with the following method. In step 12, the elapsed time is calculated using a timer circuit from the time when the power was turned off last time and the time when the power was turned on this time. Next, in step 13, an expected temperature change amount in the receiving device is calculated based on the elapsed time calculated in step 12. At this time, when calculating the expected temperature change amount from the elapsed time, in Patent Document 1, it is calculated from a function that approximates a characteristic curve that is predicted in advance, or obtained by providing a conversion table of elapsed time and temperature change amount. ing. In step 14, the expected frequency change amount is calculated from the expected temperature change amount using an approximate expression of the frequency deviation amount with respect to the temperature change amount prepared in advance.

By obtaining the frequency deviation by the above method and setting the data lock frequency according to the deviation, the pull-in time can be shortened.
JP 2002-314449 A

  In the conventional method, a temperature change amount is predicted using a measured elapsed time and a function or table of a temperature change corresponding to a previously prepared elapsed time, and further corresponding to a temperature change prepared in advance. The expected frequency deviation amount is calculated using a frequency deviation function or table. However, since the frequency deviation characteristic with respect to the temperature of the crystal unit differs depending on the crystal unit to be used, the amount of frequency deviation with respect to the temperature of the receiving unit varies depending on the receiving unit to be used. Also, the amount of change in temperature of the receiving device with respect to the elapsed time varies depending on the configuration of the receiving device and the usage status of the receiving device. In particular, when considering application to time division reception such as the DVB-H system, the power of the demodulator repeats ON / OFF, but the power of the entire receiver is ON. Unlike the system configuration used in the system, the amount of temperature change is also different. Furthermore, it is impossible to prepare functions and tables suitable for each product in advance, and the conventional method predicts the frequency deviation according to the parts, types, and usage conditions of the receiving device. Had the problem of not being able to.

  The present invention solves the above-described conventional problems, and provides a frequency deviation amount using elapsed time and past frequency deviation without preparing a function or table of temperature deviation with respect to elapsed time and frequency deviation with respect to temperature change in advance. By accurately predicting the carrier frequency according to the configuration of the receiving device and the usage state of the receiving device and the frequency deviation amount of the sampling frequency, it is intended to provide a receiving device with a short synchronization pull-in time. To do.

  In order to solve the above-described conventional problems, a receiving apparatus of the present invention includes a quadrature demodulation unit, a frequency error detection unit, an oscillation unit, a control unit, and an estimation unit, and the quadrature demodulation unit is output from the oscillation unit. The received digital signal is quadrature demodulated based on the received signal, and the frequency error detector detects an error between the oscillation frequency of the oscillator and the carrier frequency of the digital signal from the output of the orthogonal demodulator, The control unit controls the oscillation frequency of the oscillation unit based on the output of the frequency error detection unit, and the estimation unit includes a plurality of units before turning off a part or all of the power of the reception device. From the output of the control unit at the time (first time), the oscillation frequency of the oscillation unit at the time of turning on the power again (second time) is estimated, and the control unit further turns on the power again when doing (Second time), and controls the oscillating unit on the basis of the estimated oscillation frequency.

  With this configuration, the synchronization pull-in time can be shortened and power consumption can be reduced.

  According to the configuration of the present invention, the synchronization pull-in time can be shortened by predicting the frequency deviation caused by the temperature change of the receiving device.

  In addition, since the frequency deviation until the next reception is predicted from the tendency of the frequency deviation in the past, a wide variety of frequency deviations that differ depending on the configuration of the receiving device and the usage status of the receiving device can be accurately predicted. Can be realized.

  Further, by shortening the synchronization pull-in time, it is possible to reduce power consumption, and further, this effect can be maximized in the time division receiver.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 shows a block diagram of a receiving apparatus according to Embodiment 1 of the present invention. Here, for example, the DVB-H system will be described as an example. The DVB-H transmission system is an extension of the DVB-T transmission system, and the basic configuration is the same. In FIG. 1, 10 is an antenna for receiving broadcast waves, 11 is an A / D converter, 12 is an orthogonal demodulator, 13 is a demodulator, 14 is an error corrector, 15 is a time information extractor, and 16 is an error detector. , 17 is a loop filter, 18 is a storage unit, 19 is an estimation unit, 20 is a power supply control unit, 21 is a demodulation circuit, and 22 is an oscillator. The antenna 10 receives a DVB-H signal that is time-divided for each channel, selects a channel with a tuner, converts the signal of the selected channel into an intermediate frequency signal, and performs analog conversion with an A / D converter 11. After the data is converted into digital data, it is converted into an OFDM baseband signal by orthogonal demodulation at the orthogonal demodulation unit 12. Thereafter, the demodulation unit 13 performs demodulation processing such as FFT processing and transmission path equivalence, and the error correction unit 14 performs error correction on the demodulated data. In the DVB-H method, data is transmitted in a time-sharing manner for each program in a time-sharing manner, and the IP packet data in the burst includes time information of a time interval from the IP packet to the next burst. Yes. The time information extraction unit 15 extracts the time information. The power supply control unit 20 controls the power supply of the demodulation circuit 21 based on the time information obtained from the time information extraction unit 15. The error detection unit 16 detects the difference between the carrier frequency extracted from the baseband signal and the data lock frequency, and inputs it to the loop filter 17. The value output from the loop filter 17 is input to an NCO (Numerally Controlled Oscillator) oscillator 22. The longer the error between the initial carrier frequency and the data lock frequency, the longer the time required for the output value of the loop filter 17 to converge. If the convergence is below a certain level, it can be determined that the synchronization is established. That is, the synchronization pull-in time can be shortened by reducing the error between the initial carrier frequency and the data lock frequency. Factors that increase this error include deviations in the oscillation frequency of the oscillator 22 due to the reception environment, the temperature of the reception device, and the like. In general, an oscillator using a crystal resonator has temperature characteristics, and the oscillation frequency depends on the temperature inside the receiver. In a normal frequency synchronization system, once synchronization is drawn, it is possible to follow the frequency deviation due to this temperature change.

  On the other hand, consider carrier frequency synchronization in the DVB-H system. As described above, the DVB-H system employs time slicing in which time division multiplex transmission is performed for each program. In the receiving device, the broadcast signal is received and demodulated only during the time when the desired signal arrives. During other times, the power of the demodulation circuit 21 is turned off to reduce power consumption. Then, the power of the demodulating circuit 21 is turned on at the time when the desired program signal of the next burst arrives and the time required for pulling in. Thus, when performing time division reception, synchronization must be established for each burst. At this time, since the ratio of the synchronization acquisition time to the burst length is large, power consumption due to the synchronization acquisition time is large. Therefore, reducing the synchronization pull-in time for each burst is an important issue for reducing power consumption in the DVB-H system.

  FIG. 3 shows the temperature variation of the receiver in the DVB-H system and the time variation of the oscillation frequency of the crystal. In the DVB-H system, the power source of the demodulation circuit 21 is controlled for each burst. Among the reception devices, a decoding circuit that decodes demodulated data into video or audio, a display device that displays a broadcast program, etc. It continues to work. Therefore, the temperature change between bursts is not constant because it depends on the configuration of the receiving apparatus and the usage situation. Further, since the burst length is about several hundred milliseconds and the interval between bursts is about several seconds, the frequency deviation due to the temperature change of the receiving apparatus between the bursts cannot be ignored. However, it is considered that the operation of these receiving apparatuses is periodic to some extent, and the temperature and frequency deviation also change relatively slowly.

  Therefore, in the present invention, the frequency deviation of the carrier frequency across the burst is predicted based on the past frequency deviation and the elapsed time. As a prediction method, for example, there is a method of predicting the convergence value of the next burst from the convergence value of the loop filter in the past burst using the least square method: MMSE (Minimum Mean Square Error). The least square method is a general method of determining function parameters so that the sum of squares of a difference between a measured value and a theoretical value obtained from a model function is minimized. The prediction method using MMSE is shown below.

  FIG. 5 shows a control flow for predicting the carrier frequency deviation when the power is turned off, which is used in the first embodiment. The prediction is performed immediately before the power of the demodulation circuit 21 is turned off.

  First, in step 22, it is confirmed whether a synchronization state is established in the current burst. Here, if the synchronization state is not established, the convergence value is not predicted. If synchronization is established, in step 23, the convergence value of the loop filter in the current burst is acquired, and further information related to synchronization such as the convergence value of the loop filter in the past burst and time information stored in the storage unit 18. Is read. Here, at least one or more past synchronization information in the past is stored.

  Next, in step 24, the time information extraction unit 15 extracts time information indicating the time when the power of the next burst is turned on.

  In step 25, the estimation unit 19 approximates the tendency of the convergence value of the loop filter with respect to time by a function using MMSE based on the information on the convergence value of the loop filter in the past burst read in step 23. Determine the parameters of the function. For example, when past convergence values are approximated by a straight line, the slope and intercept of the straight line are determined as function parameters. Furthermore, an optimum predicted value of the convergence value of the loop filter in the next burst is obtained from the approximated function and the time information obtained from the time information extraction unit 15. The predicted value and the synchronization information in the current burst, and if necessary, the past synchronization information are stored in the storage unit 18 (step 26), and the power of the demodulation circuit 21 is turned off. The stored convergence value is preferably a value immediately before the demodulating circuit 21 is turned off, but may be an arbitrary time after the synchronization is established in the burst until the power is turned off.

  Next, FIG. 6 shows a control flow when the power is turned on. After the power is turned on again, in step 20, the synchronization information stored in the storage unit 18 is read. Then, the read prediction value is set as the initial value of the loop filter in the burst (step 21). In this way, the synchronization pull-in time can be shortened by predicting the convergence value of the loop filter value. Normally, in the next burst, the time for which the demodulating circuit 21 is turned on is set earlier than the time determined by the time information by an estimated pull-in time. Thus, by predicting the convergence value of the loop filter at the time of power ON considering the pull-in time, faster synchronization is possible.

  Instead of using MMSE, an LMS (Least Mean Square Algorithm) algorithm may be used. The LMS algorithm is a method for minimizing the mean square error based on the steepest descent method, and has a small amount of calculation and is a typical adaptive algorithm. In addition, LMS can be processed sequentially. When MMSE is used, the convergence value and time information of past bursts must be stored in the storage unit 18, whereas when LMS is used, calculation is performed. It is only necessary to memorize the parameters of the approximate function.

  In addition to this, as a method of estimating the function, it may be estimated using a sequential least squares RLS (Recursive Least Square) algorithm, a jump algorithm, a learning identification method, or the like.

  Instead of estimating the convergence value when the power is turned off, the convergence value of the current burst may be stored and estimated at the moment when the power of the demodulation circuit 21 is turned on in the next burst. At this time, the time information may be obtained by storing the time information obtained from the previous burst, or may be obtained by a timer circuit provided in the receiving apparatus other than the demodulator.

  In addition, it is possible to reduce an estimation error due to a reception environment or the like by weighting the predicted fluctuation value of the convergence value. At this time, the accuracy can be improved by changing the weighting coefficient according to the reception environment.

  By the above control, not only the frequency deviation due to temperature change but also the fluctuation of frequency deviation due to other factors can be predicted at the same time, and the pull-in time can be shortened.

  Furthermore, by shortening the pull-in time for each burst, the power-on time of the receiving apparatus can be shortened, which has a great effect on power consumption reduction.

(Embodiment 2)
FIG. 4 shows a block diagram of a receiving apparatus according to Embodiment 2 of the present invention. Here, correction of the frequency deviation of the sampling clock will be described. 4, the antenna 10, the A / D conversion unit 11, the quadrature demodulation unit 12, the demodulation unit 13, the error correction unit 14, the time information extraction unit 15, and the power supply control unit 20 are the same as those in FIG. The description is omitted.

  The A / D converter 11 samples the input signal based on the signal output from the oscillator 32, and converts analog data into digital data. In the error detection unit 26, the timing offset of the clock is detected and input to the loop filter 27. The output of the loop filter 27 is input to the oscillator 32 to control the oscillation frequency. The convergence value estimation unit 29 predicts the frequency deviation of the sampling clock over the burst based on the past frequency deviation and the elapsed time.

  FIG. 7 shows a control flow for predicting the sampling frequency deviation used in the second embodiment when the power is turned off. The prediction is performed immediately before the power of the demodulation circuit 31 is turned off.

  First, in step 32, it is confirmed whether a synchronization state is established in the current burst. Here, if the synchronization state is not established, the convergence value is not predicted. If synchronization is established, in step 33, the convergence value of the loop filter in the current burst is acquired, and further information related to synchronization such as the convergence value of the loop filter in the past burst and time information stored in the storage unit 28. Is read. Here, at least one or more past synchronization information in the past is stored.

  Next, in step 34, the time information extraction unit 15 extracts time information indicating the time when the next burst is turned on.

  In step 35, the estimation unit 29 approximates the tendency of the convergence value of the loop filter with respect to time by a function using MMSE based on the information on the convergence value of the loop filter in the past burst read in step 33. Determine the parameters of the function. For example, when past convergence values are approximated by a straight line, the slope and intercept of the straight line are determined as function parameters. Furthermore, an optimum predicted value of the convergence value of the loop filter in the next burst is obtained from the approximated function and the time information obtained from the time information extraction unit 15. The predicted value and the synchronization information in the current burst, and if necessary, the past synchronization information are stored in the storage unit 28 (step 36), and the power of the demodulation circuit 31 is turned off. The stored convergence value is preferably a value immediately before the demodulating circuit 31 is turned off, but may be an arbitrary time after the synchronization is established in the burst until the power is turned off.

  Next, FIG. 8 shows a control flow when the power is turned on. After the power is turned on again, in step 30, the synchronization information stored in the storage unit 28 is read. Then, the read prediction value is set as the initial value of the loop filter in the burst (step 31). In this way, the synchronization pull-in time can be shortened by predicting the convergence value of the loop filter value. Normally, in the next burst, the time for which the demodulating circuit 31 is turned on is set earlier than the time determined by the time information by an estimated pull-in time. Thus, by predicting the convergence value of the loop filter at the time of power ON considering the pull-in time, faster synchronization is possible.

  Further, instead of using MMSE, an LMS algorithm may be used. In addition, the LMS can perform sequential processing. When using the MMSE, the convergence value of the past burst and time information must be stored in the storage unit 28, whereas when using the LMS, the calculation is performed. It is only necessary to memorize the parameters of the approximate function.

  In addition, as a method for estimating a function, estimation may be performed using a sequential least squares RLS algorithm, a jump algorithm, a learning identification method, or the like.

  Instead of estimating the convergence value when the power is turned off, the convergence value of the current burst may be stored and estimated at the moment when the power of the demodulation circuit 31 is turned on in the next burst. At this time, the time information may be obtained by storing the time information obtained from the previous burst, or may be obtained by a timer circuit provided in the receiving apparatus other than the demodulator.

  In addition, it is possible to reduce an estimation error due to a reception environment or the like by weighting the predicted fluctuation value of the convergence value. At this time, the accuracy can be improved by changing the weighting coefficient according to the reception environment.

  By the above control, not only the frequency deviation of the clock frequency due to the temperature change but also the fluctuation of the clock frequency deviation due to other factors can be predicted at the same time.

  In the first embodiment of the present invention, the frequency deviation prediction of the carrier frequency is described separately, and in the second embodiment of the present invention, the frequency deviation prediction of the sampling clock is described separately. However, these can be mounted in parallel in the receiving apparatus.

  In Embodiments 1 and 2, the DVB-H scheme is taken as an example to describe carrier frequency synchronization and sampling frequency synchronization in a time division receiver, but the present invention is not limited to time division receivers. Any receiving apparatus that turns off the power supply several times and turns on the power supply again can be applied to carrier frequency synchronization and sampling frequency synchronization of the receiving apparatus.

  Note that the receiving apparatus described above is typically realized as an LSI which is an integrated circuit. These may be individually made into one chip, or may be made into one chip so as to include all or part thereof.

  The name used here is LSI, but it may also be called IC, system LSI, super LSI, or ultra LSI depending on the degree of integration.

  Further, the method of circuit integration is not limited to LSI, and implementation with a dedicated circuit or a general-purpose processor is also possible. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.

  Further, if integrated circuit technology comes out to replace LSI's as a result of the advancement of semiconductor technology or a derivative other technology, it is naturally also possible to carry out function block integration using this technology. Biotechnology can be applied.

  The receiver according to the present invention has a carrier recovery unit and a sampling frequency recovery unit that can shorten the synchronization acquisition time with respect to the time division receiver, and is useful as a European DVB-H demodulator or the like. Further, the present invention can be applied to the use of a receiving apparatus that employs a receiving method in which a demodulator is turned on / off in a time division manner.

The block diagram of the receiver which concerns on Embodiment 1 of this invention Flowchart relating to synchronization pull-in technique according to the conventional embodiment Temperature and frequency deviation diagram according to the embodiment of the present invention Block diagram of receiving apparatus according to Embodiment 2 of the present invention The figure which shows the control flow at the time of the power supply OFF which concerns on Embodiment 1 of this invention The figure which shows the control flow at the time of the power supply ON which concerns on Embodiment 1 of this invention The figure which shows the control flow at the time of the power supply OFF which concerns on Embodiment 2 of this invention The figure which shows the control flow at the time of the power supply ON which concerns on Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Antenna 11 A / D conversion part 12 Orthogonal demodulation part 13 Demodulation part 14 Error correction part 15 Time information extraction part 16 Carrier frequency error detection part 17 Loop filter 18 Storage part 19 Estimation part 20 Power supply control part 21 Demodulation circuit 22 Oscillator 26 Sampling Frequency error detection unit 27 Loop filter 28 Storage unit 29 Estimation unit 31 Demodulation circuit

Claims (30)

A receiving device that receives and demodulates a digital signal,
An orthogonal demodulation unit, a frequency error detection unit, an oscillation unit, a control unit, an estimation unit,
The quadrature demodulating unit orthogonally demodulates the received digital signal based on a signal output from the oscillating unit,
The frequency error detection unit detects an error between the oscillation frequency of the oscillation unit and the carrier frequency of the digital signal from the output of the quadrature demodulation unit,
The control unit controls the oscillation frequency of the oscillation unit based on the output of the frequency error detection unit,
The estimator turns on the power again (second time) from the output of the controller at a plurality of times (first time) before turning off a part or all of the power of the receiving device. A receiver that estimates an oscillation frequency of the oscillation unit at the time, and the control unit further controls the oscillation unit based on the estimated oscillation frequency at a time (second time) when the power is turned on again . The receiving apparatus according to claim 1, wherein the control unit includes a loop filter. The digital signal is obtained by time-division multiplexing a plurality of different services, and the receiving device includes a power control unit,
The receiving apparatus according to claim 1, wherein the power control unit turns on the power of the receiving apparatus for a period including a desired service period, and turns off a part or all of the power of the receiving apparatus for the remaining period. The plurality of times (first times) are times when part or all of the power of the receiving apparatus is turned off in at least two or more power-on periods among the past power-on periods. The receiving device described. In the plurality of times (first times), a part or all of the power of the receiving apparatus is turned off after synchronization of carrier frequency is established in at least two or more power-on periods in the past power-on periods. The receiving apparatus according to claim 1, wherein the time is an arbitrary time until the setting. The receiving device includes a time information extraction unit, and the time when the power is turned on again by the power control unit (second time) is based on the time information extracted from the reception data by the time information extraction unit. The receiving apparatus according to claim 1, wherein the receiving apparatus is determined. The estimation unit oscillates the oscillation unit at a time (second time) when the power is turned on again using a least square method based on the output of the control unit at the plurality of times (first time). The receiving apparatus according to claim 1, wherein the frequency is estimated. The estimation unit, based on the output of the control unit at the plurality of times (first time), the oscillation frequency of the oscillation unit at the time (second time) when the power is turned on again using the LMS algorithm The receiving apparatus according to claim 1, wherein: The estimation unit estimates an oscillation frequency of the oscillation unit at a time (second time) when the power is turned on again at a time before turning off a part or all of the power of the receiving device. Receiver. The said receiving apparatus is provided with the memory | storage part, and memorize | stores the information regarding the oscillating frequency of the said oscillating part in the time (second time) when the said power supply is estimated again estimated in the said estimation part for a fixed period. Receiver. The receiving device according to claim 1, wherein the estimation unit estimates an oscillation frequency of the oscillation unit at a second time at a time when the power is turned on again (second time). The said receiving apparatus is provided with the memory | storage part, and memorize | stores the information required in order to estimate the oscillation frequency in the said oscillation part for a fixed period at the time (2nd time) which powers on again. Receiver device. A receiving device that receives and demodulates a digital signal,
A sampling unit, a frequency error detection unit, an oscillation unit, a control unit, an estimation unit,
The sampling unit samples the received digital signal based on a signal output from the oscillation unit,
The frequency error detection unit detects an error between the oscillation frequency of the oscillation unit and the sampling frequency of the digital signal from the output of the sampling unit,
The control unit controls the oscillation frequency of the oscillation unit based on the output of the frequency error detection unit,
The estimator turns on the power again (second time) from the output of the controller at a plurality of times (first time) before turning off a part or all of the power of the receiving device. A receiver that estimates an oscillation frequency of the oscillation unit at the time, and the control unit further controls the oscillation unit based on the estimated oscillation frequency at a time (second time) when the power is turned on again . The receiving device according to claim 13, wherein the control unit includes a loop filter. The digital signal is obtained by time-division multiplexing a plurality of different services, and the receiving device includes a power control unit,
The receiving apparatus according to claim 13, wherein the power control unit turns on the power of the receiving apparatus for a period including a desired service period, and turns off a part or all of the power of the receiving apparatus for the remaining period. The plurality of times (first times) are times when part or all of the power of the receiving apparatus is turned off in at least two or more power-on periods in the past power-on periods. The receiving device described. In the plurality of times (first times), a part or all of the power of the receiving apparatus is turned off after synchronization of sampling frequencies is established in at least two or more power-on periods in the past power-on periods. The receiving device according to claim 13, which is an arbitrary time until the time is reached. The receiving device includes a time information extraction unit, and the time when the power is turned on again by the power control unit (second time) is based on the time information extracted from the reception data by the time information extraction unit. 14. The receiving apparatus according to claim 13, wherein the receiving apparatus is determined. The estimation unit oscillates the oscillation unit at a time (second time) when the power is turned on again using a least square method based on the output of the control unit at the plurality of times (first time). The receiving device according to claim 13, wherein the frequency is estimated. The estimation unit, based on the output of the control unit at the plurality of times (first time), the oscillation frequency of the oscillation unit at the time (second time) when the power is turned on again using the LMS algorithm The receiver according to claim 13, wherein the receiver is estimated. The estimation unit estimates an oscillation frequency of the oscillation unit at a time (second time) when the power is turned on again at a time before turning off a part or all of the power of the receiving device. Receiver. The said receiving apparatus comprises a memory | storage part, The information regarding the oscillating frequency of the said oscillating part in the time (2nd time) which powers on again estimated by the said estimation part is memorize | stored for a fixed period. Receiver. The receiving device according to claim 13, wherein the estimation unit estimates an oscillation frequency of the oscillation unit at a second time at a time when the power is turned on again (second time). 24. The receiver according to claim 23, wherein the receiving device includes a storage unit, and stores information necessary for estimating an oscillation frequency in the oscillation unit for a certain period of time at the time when the power is turned on again (second time). Receiver device. An integrated circuit of a receiving device that receives and demodulates a digital signal,
An orthogonal demodulation unit, a frequency error detection unit, an oscillation unit, a control unit, an estimation unit,
The quadrature demodulating unit orthogonally demodulates the received digital signal based on a signal output from the oscillating unit,
The frequency error detection unit detects an error between the oscillation frequency of the oscillation unit and the carrier frequency of the digital signal from the output of the quadrature demodulation unit,
The control unit controls the oscillation frequency of the oscillation unit based on the output of the frequency error detection unit,
The estimator turns on the power again (second time) from the output of the controller at a plurality of times (first time) before turning off a part or all of the power of the receiving device. An integrated circuit that estimates an oscillation frequency of the oscillation unit in the control circuit, and the control unit further controls the oscillation unit based on the estimated oscillation frequency at a time when the power is turned on again (second time) . An integrated circuit of a receiving device that receives and demodulates a digital signal,
A sampling unit, a frequency error detection unit, an oscillation unit, a control unit, an estimation unit,
The sampling unit samples the received digital signal based on a signal output from the oscillation unit,
The frequency error detection unit detects an error between the oscillation frequency of the oscillation unit and the sampling frequency of the digital signal from the output of the sampling unit,
The control unit controls the oscillation frequency of the oscillation unit based on the output of the frequency error detection unit,
The estimator turns on the power again (second time) from the output of the controller at a plurality of times (first time) before turning off a part or all of the power of the receiving device. An integrated circuit that estimates an oscillation frequency of the oscillation unit in the control circuit, and the control unit further controls the oscillation unit based on the estimated oscillation frequency at a time when the power is turned on again (second time) . A receiving method for receiving and demodulating a digital signal,
Quadrature demodulation of the received digital signal based on a defined oscillation frequency,
From the quadrature demodulated signal, an error signal of the oscillation frequency and the carrier frequency of the digital signal is detected,
Generating a control signal from the error signal;
A method of controlling the oscillation frequency from the control signal,
From a control signal at a plurality of times (first time) before turning off a part or all of the power supply of the receiving device, a control signal at a time of turning on the power again (second time) is estimated,
A receiving method for controlling the oscillation frequency based on the estimated control signal at the second time. A receiving method for receiving and demodulating a digital signal,
Sampling the received digital signal based on a defined oscillation frequency;
From the sampled signal, an error signal between the oscillation frequency and the sampling frequency is detected,
Generating a control signal from the error signal;
A method of controlling the oscillation frequency from the control signal,
From a control signal at a plurality of times (first time) before turning off a part or all of the power supply of the receiving device, a control signal at a time of turning on the power again (second time) is estimated,
A receiving method for controlling the oscillation frequency based on the estimated control signal at the second time. A tuner that receives a digital signal, a receiving device that demodulates the received digital signal, a decoding device that converts data demodulated by the receiving device into a video / audio signal, and an output device that displays and outputs the decoded signal And
The receiving device includes an orthogonal demodulation unit, a frequency error detection unit, an oscillation unit, a control unit, an estimation unit,
The quadrature demodulating unit orthogonally demodulates the received digital signal based on a signal output from the oscillating unit,
The frequency error detection unit detects an error between the oscillation frequency of the oscillation unit and the carrier frequency of the digital signal from the output of the quadrature demodulation unit,
The control unit controls the oscillation frequency of the oscillation unit based on the output of the frequency error detection unit,
The estimator turns on the power again (second time) from the output of the controller at a plurality of times (first time) before turning off a part or all of the power of the receiving device. A receiver that estimates an oscillation frequency of the oscillation unit at the time, and the control unit further controls the oscillation unit based on the estimated oscillation frequency at a time (second time) when the power is turned on again . A tuner that receives a digital signal, a receiving device that demodulates the received digital signal, a decoding device that converts data demodulated by the receiving device into a video / audio signal, and an output device that displays and outputs the decoded signal And
The receiving device includes a sampling unit, a frequency error detection unit, an oscillation unit, a control unit, an estimation unit,
The sampling unit samples the received digital signal based on a signal output from the oscillation unit,
The frequency error detection unit detects an error between the oscillation frequency of the oscillation unit and the sampling frequency of the digital signal from the output of the sampling unit,
The control unit controls the oscillation frequency of the oscillation unit based on the output of the frequency error detection unit,
The estimator turns on the power again (second time) from the output of the controller at a plurality of times (first time) before turning off a part or all of the power of the receiving device. A receiver that estimates an oscillation frequency of the oscillation unit at the time, and the control unit further controls the oscillation unit based on the estimated oscillation frequency at a time (second time) when the power is turned on again .

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