JP2013123155A - Receiver, reception method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable channel scan even when a signal from an antenna is supplied after frequency conversion in a relay, for example.SOLUTION: A receiver comprises: a control unit which causes a relay, which receives a signal in a desired frequency band to convert into a signal in a frequency band assigned to the receiver and then outputs the converted signal, to receive signals while sequentially changing the frequency band; and a measurement unit for measuring a spectrum of a signal supplied from the relay after the frequency conversion. This technique is applicable to a receiver connected with a single-cable system.

Description

  The present technology relates to a receiving device, a receiving method, and a program, and in particular, a receiving device that can perform channel scanning even when a signal from an antenna is supplied after frequency conversion in a repeater, for example, and receiving The present invention relates to a method and a program.

  As a receiving form of satellite television broadcasting, a switch serving as a repeater is provided between a plurality of satellite antennas and a receiving device, and a satellite antenna and a receiving program are selected and received by switching the input of the switch from the receiving device. There are various forms.

  FIG. 1 is a diagram illustrating a first example of a satellite antenna connection method. In the example of FIG. 1, satellite antennas # 0 to #X are each connected to the input of the switch 1 by a coaxial cable, and the output of the switch 1 and the receiving device 2 are connected by a single coaxial cable.

  The switch 1 selects an input requested by the receiving device 2, that is, a satellite antenna, and outputs an IF signal supplied from the selected satellite antenna to the receiving device 2. Each satellite antenna consists of an RF antenna and an LNB (Low Noise Block Converter). The switch 1 is supplied with an IF signal obtained by performing frequency conversion by the LNB.

  The receiving device 2 performs various processes such as demodulation on the IF signal supplied from the switch 1, and acquires program data received by the satellite antenna that requested the selection.

  FIG. 2 is a diagram illustrating a second example of a satellite antenna connection method. In the example of FIG. 2, satellite antennas # 0 to #X are each connected to the input of the switch 1 by a coaxial cable. Further, the receivers 2-1 to 2-N are connected to the output of the switch 1 by N coaxial cables, respectively.

  The switch 1 selects a satellite antenna according to each request of the receiving apparatuses 2-1 to 2-N, and outputs the IF signal supplied from the selected satellite antenna to the receiving apparatus that has requested the IF signal.

  The connection method of FIG. 2 is normally used when there are a plurality of receiving devices such as an apartment house. However, since it is necessary to supply an IF signal according to the request of each receiving device (user), the switch 1 It is necessary to wire between the receiving devices with the same number of cables as the receiving devices.

  Therefore, in order to simplify the wiring, a connection method is used in which the switch 1 converts a signal in a peripheral frequency band of a desired reception channel of each reception device into a signal having a frequency assigned to each reception device and outputs the signal. . According to this connection method, one cable is connected to the output of the switch 1, and the one branch of the one cable is connected to each receiving apparatus.

  Hereinafter, as appropriate, a peripheral frequency band of a reception channel desired by each receiving apparatus is referred to as an IF band, and a frequency band assigned to each receiving apparatus is referred to as a user band. The switch 1 converts an IF band signal supplied from a desired satellite antenna into a user band signal assigned to a receiving apparatus that has requested the IF band signal, and outputs the signal.

  FIG. 3 is a diagram illustrating a third example of a satellite antenna connection method. In the example of FIG. 3, satellite antennas # 0 to #X are each connected to the input of the switch 1 by a coaxial cable. In addition, one coaxial cable is connected to the output of the switch 1. One coaxial cable connected to the output of the switch 1 branches, and the receivers 2-1 to 2-N are connected to the branch destination.

  The switch 1 converts a desired IF band signal of each receiving device into a user band signal, and frequency-multiplexes and outputs the signal. The multiplexed signal output from the switch 1 is supplied to each of the receiving apparatuses 2-1 to 2-N.

  FIG. 4 is a diagram illustrating an example of a multiplexed signal output from the switch 1 of FIG. The user band 1 in FIG. 4 is a frequency band assigned to the receiving device 2-1, and the user band 2 is a frequency band assigned to the receiving device 2-2. Each of the receiving apparatuses 2-1 to 2-N receives a desired channel by selecting a user band signal allocated to itself from the signal supplied from the switch 1.

  Hereinafter, the connection method of FIG. 3 is referred to as a single cable method as appropriate. The single cable system is defined in Non-Patent Document 1, for example. Non-Patent Document 1 defines a single cable system that distributes signals in a desired frequency band of a maximum of two satellite antennas (total 8 LNBs) on a single coaxial cable shared by a maximum of eight users. ing.

  By the way, various receiving apparatuses including a receiving apparatus for satellite television broadcasting are equipped with a channel scanning function for automatically detecting which frequency band is used for broadcasting.

  The channel scan is a function that scans a receivable channel in an actual environment and stores information about a receivable channel obtained by the scan in a memory or the like provided in the receiving apparatus. The user can select a channel to be received from channels in which channel information is stored. In general, the channel scan is performed in an unknown situation (blind situation) where information on receivable channels is not given.

  Here, the channel scan in the blind will be described with reference to the flowchart of FIG. The processing in FIG. 5 is performed by, for example, the receiving device 2 in FIG.

  In step S1, the receiving apparatus 2 sets a channel scan start frequency.

  In step S2, the receiving apparatus 2 sets a minimum symbol rate (SR). For example, in satellite television broadcasting, a predetermined rate of 1 to 45 Msps (symbol / second) is used as the symbol rate of each broadcast channel. In this case, 1 Msps is set as the minimum Symbol Rate.

  In step S3, the receiving device 2 performs reception processing such as demodulation and decoding on the IF signal supplied from the satellite antenna via the switch 1.

  In step S4, the receiving device 2 determines whether or not synchronization has been established by the receiving process.

  When it is determined in step S4 that the synchronization has not been established, in step S5, the receiving apparatus 2 determines whether or not the current symbol rate setting value has reached the maximum symbol rate, for example, 45 Msps.

  If it is determined in step S5 that the maximum symbol rate has not been reached, in step S6, the receiving device 2 increments the set value of the symbol rate, and repeats the processing from step S3.

  On the other hand, if it is determined in step S4 that the synchronization has been established, in step S7, the receiving device 2 stores the currently set frequency and symbol rate information in the memory as channel information.

  After the channel information is stored in step S7 or when it is determined in step S5 that the symbol rate setting value has reached the maximum symbol rate, in step S8, the receiver 2 sets the frequency setting value to the maximum frequency. It is determined whether it has been reached.

  If it is determined in step S8 that the maximum frequency has not been reached, in step S9, the receiving apparatus 2 increments the frequency setting value and repeats the processing from step S2 onward.

  On the other hand, if it is determined in step S8 that the maximum frequency has been reached, the receiving device 2 ends the process. As described above, the blind channel scan is performed by changing the frequency to be received and the symbol rate within a range that can be obtained, and storing the information of the channel that has established synchronization.

“Satellite signal distribution over a single coaxial cable in single dwelling installations (BS EN 50494)”

  The above-described blind channel scan cannot be performed when the satellite antenna connection method is the single cable method of FIG. That is, since the IF band signal is always converted to the user band signal in the switch 1, the receiving apparatus cannot determine whether or not synchronization can be established by sweeping the frequency of the IF band.

  The present technology has been made in view of such a situation. For example, a channel scan can be performed even when a signal from an antenna is supplied after being subjected to frequency conversion in a repeater.

  A receiving device according to an aspect of the present technology receives a signal in a desired frequency band, and causes a repeater that converts the signal into a frequency band signal allocated to the receiving device to output the signal, sequentially changing the frequency band. A control unit; and a measurement unit that measures a spectrum of a signal after frequency conversion supplied from the repeater.

  An estimation unit that estimates channel candidates used for broadcasting based on the spectrum can be further provided. In this case, the control unit can cause the repeater to receive a signal of the candidate channel.

  The signal processor that performs signal processing including demodulation and decoding on the frequency-converted signal supplied from the repeater that has received the candidate channel signal, and the candidate that has established synchronization by the signal processing And a storage unit for storing information on the channels.

  The information stored in the storage unit may include frequency information of the candidate channel.

  The repeater outputs a signal obtained by frequency-multiplexing a signal in a frequency band assigned to each receiving device on one coaxial cable to which a plurality of receiving devices including the receiving device itself is connected at the branch destination. It can be a device. In this case, the control unit can transmit a DiSEqC standard command to the repeater to control the reception frequency band.

  The signal of the desired frequency band can be a signal supplied from an antenna. The antenna may be an antenna that receives terrestrial broadcasting or an antenna that receives satellite broadcasting.

  The signal of the desired frequency band can be an RF signal or an IF signal.

  In one aspect of the present technology, a repeater that receives a signal in a desired frequency band, converts the signal into a signal in the frequency band assigned to the reception device, and outputs the signal can be received by sequentially changing the frequency band. And the spectrum of the frequency-converted signal supplied from the repeater is measured.

  According to the present technology, for example, channel scanning can be performed even when a signal from an antenna is supplied after being frequency-converted in a repeater.

It is a figure which shows the 1st example of the connection system of a satellite antenna. It is a figure which shows the 2nd example of the connection system of a satellite antenna. It is a figure which shows the 3rd example of the connection system of a satellite antenna. It is a figure which shows the example of the output of the switch in a Single Cable system. It is a flowchart explaining the channel scan in a blind. It is a block diagram showing an example of composition of a receiving device concerning one embodiment of this art. It is a figure explaining frequency inversion. It is a figure which shows the example of switching of a receiving channel. It is a figure which shows the data structure of a DiSEqC command. It is a figure which shows the data structure of an ODU_Channel_change command. It is a flowchart explaining a spectrum measurement process. It is a flowchart explaining a candidate channel selection confirmation process. It is a block diagram which shows the structural example of a receiving system. It is a block diagram which shows the structural example of a computer.

<Configuration of receiving device>
FIG. 6 is a block diagram illustrating a configuration example of a receiving device according to an embodiment of the present technology.

  A receiving device 2-1 in FIG. 6 is a receiving device connected to the switch 1 by the single cable method shown in FIG.

  That is, each of the satellite antennas # 0 to #X is connected to the input of the switch 1 by a coaxial cable, and one coaxial cable is connected to the output of the switch 1. One coaxial cable connected to the output of the switch 1 is branched, and receiving devices 2-1 to 2-N including the receiving device 2-1 are connected to the branch destination. From the switch 1, a multiplexed signal shown in FIG. 4 obtained by converting a signal of a desired IF band of each receiving device into a signal of a user band and frequency multiplexing is output onto the coaxial cable.

  In the receiving device 2-1, blind channel scanning is performed using the multiplexed signal supplied from the switch 1.

  The reception device 2-1 includes a reception unit 11, a signal processing unit 12, a spectrum measurement unit 13, an estimation unit 14, a control unit 15, and a storage unit 16. The signal processing unit 12 includes a demodulation unit 21 and a decoding unit 22. The multiplexed signal output from the switch 1 is input to the receiving unit 11.

  The receiving unit 11 selects the user band assigned to the receiving device 2-1 and extracts the user band 1 signal from the multiplexed signal supplied from the switch 1. The reception unit 11 outputs the user band 1 signal extracted from the multiplexed signal to the demodulation unit 21 of the signal processing unit 12.

  The demodulator 21 performs a demodulation process including each process such as A / D conversion, orthogonal demodulation, FFT (Fast Fourier Transform) operation, equalization, etc. on the signal supplied from the receiver 11.

  Further, the demodulating unit 21 appropriately performs frequency inversion correction on the IF signal supplied from the receiving unit 11 under the control of the control unit 15. When the switch 1 is a switch that uses the lower sideband component of the upper sideband component and lower sideband component of the mixer (frequency converter) output as the user band signal, the user band signal is: As shown in FIG. 7, the signal is a frequency-inverted signal with respect to the IF band signal. The demodulator 21 corrects the user band signal that has undergone frequency inversion so that the signal has the same spectrum as the original IF band signal. In the single cable system, a switch that uses the lower sideband component of the mixer output as a user band signal is used.

  A signal obtained by performing frequency inversion correction and demodulation processing by the demodulation unit 21 is supplied to the decoding unit 22 and the spectrum measurement unit 13.

  When the decoding unit 22 performs processing such as error correction decoding on the signal supplied from the demodulation unit 21 and can correctly perform error correction decoding, synchronization can be established. TS (Transport Stream) is output to the subsequent stage. In addition, the decoding unit 22 outputs a TS Lock signal indicating that synchronization has been established to the control unit 15.

  The spectrum measurement unit 13 measures the power of the signal supplied from the demodulation unit 21 during channel scanning. The spectrum measurement unit 13 outputs information on the power of the signal at each frequency within a predetermined frequency band, which is obtained by sequentially changing the IF band, to the estimation unit 14.

  The estimation unit 14 estimates a broadcast channel candidate that is a channel used for broadcasting, based on the power information measured by the spectrum measurement unit 13. The estimation unit 14 has information regarding the spectrum shape of a channel actually used as a broadcast channel. For example, the estimation unit 14 determines a channel whose spectrum shape represented by the power measured by the spectrum measurement unit 13 approximates the spectrum shape of the broadcast channel as a broadcast channel candidate. The estimation unit 14 outputs broadcast channel candidate information such as the center frequency to the control unit 15.

  The controller 15 causes the switch 1 to receive an IF signal in a predetermined frequency band during channel scanning. For example, the frequency band of the IF band is specified so as to receive a broadcast channel candidate signal determined by the estimation unit 14.

  For example, as shown in FIG. 8A, the control unit 15 controls the reception frequency band of the switch 1 by switching the IF band every 20 MHz in the range of 950 to 2150 MHz. In the example of FIG. 8A, 1200 MHz is specified as the center frequency Fif, and a signal in the IF band with a 20 MHz width centered on 1200 MHz is received by the switch 1. The IF band signal received by the switch 1 is converted into a user band 1 signal and output.

  For specifying the IF band for the switch 1, for example, an ODU_Channel_change command is used in a command (DiSEqC command) that is an extended command of the DiSEqC standard, which is adopted in the Single Cable method.

  FIG. 9 shows the data structure of the DiSEqC command. As shown in FIG. 9, the DiSEqC command is composed of a Framing that represents a command structure, an Address that represents a command transmission destination, a Command that represents a command type, Data1, and Data2. Parity (P) is added to each data.

  FIG. 10 shows the data structure of the ODU_Channel_change command. As shown in the upper part of FIG. 10, E0 is set in the Framing of the ODU_Channel_change command, and any one of 00, 10, and 11 representing the switch 1 is set in Address. In Command, 5A representing the ODU_Channel_change command is set.

  Data1 and Data2 are 8-bit information, respectively. The three bits of Bit7, Bit6, and Bit5 of Data1 indicate the number of the user band assigned to the receiving device 2-1, and the three bits of Bit4, Bit3, and Bit2 of Data1 indicate the numbers of the satellite antenna and LNB to be switched. Represent. Bit 1 of Data 1 and Bit 0 and Bit 7 to Bit 0 of Data 2 represent the frequency conversion amount T.

The frequency conversion amount T is expressed by the following equation (1).
T = round ((abs (Ft-Fo) + Fub) / S) -350 (1)

  In Equation (1), Ft is the RF frequency of the channel, and Fo is the local frequency of the LNB. Fub is the center frequency of the user band, and S is the quantization resolution (fixed at 4 MHz). In the above equation (1), the term abs (Ft−Fo) corresponds to the center frequency Fif of the IF band.

  After determining the desired center frequency Fif, the control unit 15 calculates the frequency conversion amount T from the center frequency Fif, and transmits it to the switch 1 in the ODU_Channel_change command. The command for the switch 1 may be transmitted via a coaxial cable connecting the switch 1 and the receiving device 2-1, or may be transmitted by another cable or wirelessly.

  Further, after transmitting the ODU_Channel_change command and designating the IF band, the control unit 15 designates an offset with respect to the carrier frequency within a range of, for example, −10 to +10 MHz as shown in FIG. Control.

  When the TS Lock signal is supplied from the decoding unit 22 during the channel scan, the control unit 15 stores the channel information received by the switch 1 as a broadcast channel candidate in the storage unit 16 including a flash memory, save.

  For example, information associating various channel parameters such as a symbol rate with an RF band frequency or an IF band frequency is stored in the storage unit 16 as broadcast channel information. Information on the frequency of the IF band includes information on the center frequency of the IF band. When the storage unit 16 next receives the same channel, the storage unit 16 controls the switch 1, the demodulation unit 21, and the like based on the information stored in the storage unit 16 to perform reception processing.

<Operation of receiving apparatus>
Here, the operation at the time of channel scanning of the receiving apparatus 2-1 having the above configuration will be described.

  A series of channel scans by the receiving device 2-1 includes spectrum measurement processing and candidate channel selection confirmation processing. The spectrum measurement process is a process of measuring the spectrum of a signal in a predetermined frequency band by sequentially switching IF bands. The candidate channel selection processing is processing for determining broadcast channel candidates based on the result of spectrum measurement processing, performing reception processing on the broadcast channel candidates, and confirming whether reception is actually possible.

  First, the spectrum measurement process will be described with reference to the flowchart of FIG.

  In step S31, the control unit 15 determines whether or not the switch 1 is a switch that outputs a signal in which frequency inversion occurs. Information indicating whether or not the switch outputs a signal with frequency inversion is set in advance in the receiving device 2-1 by storing it in the storage unit 16. The control unit 15 determines whether or not the switch 1 is a switch that outputs a signal in which frequency inversion occurs based on preset information.

  When it is determined in step S31 that the switch outputs a signal with frequency inversion, in step S32, the control unit 15 performs frequency inversion correction on the signal supplied from the reception unit 11 thereafter. The demodulator 21 is controlled.

  On the other hand, if it is determined in step S31 that the switch does not output a signal in which frequency inversion occurs, in step S33, the control unit 15 controls the demodulation unit 21 so as not to perform frequency inversion correction thereafter.

  In step S34, the control unit 15 transmits an ODU_Channel_change command to the switch 1 to set a channel scan start IF frequency.

  When performing the channel scan for the frequency band of FIG. 8A, the control unit 15 calculates the frequency conversion amount T based on the above equation (1) with the center frequency Fif set to 950 MHz, for example, and includes the calculated frequency conversion amount T. Generate ODU_Channel_change command. The control unit 15 transmits the generated ODU_Channel_change command to the switch 1 to receive a signal in an IF band with a 20 MHz width having a center frequency of 950 MHz. The switch 1 outputs a multiplexed signal including a user band 1 signal obtained by converting an IF band signal having a 20 MHz width having a center frequency of 950 MHz, and is supplied to the receiving device 2-1.

  In step S <b> 35, the control unit 15 sets the minimum frequency displacement as the carrier frequency offset (frequency displacement) used for the orthogonal demodulation of the demodulation unit 21. As described with reference to FIG. 8B, when the frequency displacement is designated by switching, for example, by 2 MHz in the range of −10 to +10 MHz, −10 MHz is designated as the minimum frequency displacement.

  After the IF band is set in step S34 and the frequency shift of the carrier frequency used for orthogonal demodulation is set in step S35, the receiving unit 11 extracts the user band 1 signal from the multiplexed signal supplied from the switch 1 Is done.

  In step S <b> 36, the demodulator 21 performs demodulation processing on the user band 1 signal extracted by the receiver 11. For example, before the demodulation process, the frequency inversion correction is appropriately performed by the demodulation unit 21. The demodulation unit 21 supplies the equalized signal obtained by the demodulation process to the spectrum measurement unit 13.

  In step S37, the spectrum measurement unit 13 measures the power of the signal supplied from the demodulation unit 21, and stores the measurement result in association with the current IF band setting value and the carrier frequency frequency displacement setting value. .

  In step S38, the control unit 15 determines whether or not the set value of the frequency displacement of the carrier frequency for orthogonal demodulation in the demodulation unit 21 has reached the maximum frequency displacement, for example, +10 MHz.

  When it is determined in step S38 that the set value of the frequency displacement of the carrier frequency has not reached the maximum frequency displacement, in step S39, the control unit 15 increments the frequency displacement of the carrier frequency by a predetermined width. Thereafter, the processing after step S36 is repeatedly performed. The frequency displacement of the carrier frequency is sequentially switched such as −10 MHz, −8 MHz, −6 MHz,..., +6 MHz, +8 MHz, +10 MHz, and the signal power at each frequency displacement is measured by the spectrum measurement unit 13. It will be.

  On the other hand, when it is determined in step S38 that the set value of the frequency displacement of the carrier frequency has reached the maximum frequency displacement, in step S40, the control unit 15 determines whether or not the set value of the IF band has reached the end IF frequency. Determine. When channel scanning is performed in the range of 950 to 2150 MHz as shown in FIG. 8A, 2150 MHz is the end IF frequency.

  When it is determined in step S40 that the set value of the IF band has not reached the end IF frequency, in step S41, the control unit 15 transmits an ODU_Channel_change command to the switch 1 to increment the IF frequency. The control unit 15 sets the IF band by shifting, for example, by 20 MHz, and repeats the processing after step S35.

  If, for example, the setting value of the center frequency of the IF band is 2150 MHz, it is determined in step S40 that the setting value of the IF band has reached the end IF frequency, the control unit 15 ends the process. Through the above processing, the spectrum measuring unit 13 acquires information on the power of the signal at each frequency of the entire frequency band to be subjected to channel scanning, such as 950 to 2150 MHz.

  Next, candidate channel selection confirmation processing will be described with reference to the flowchart of FIG. The process of FIG. 12 is started after the process of FIG.

  In step S51, the control unit 15 determines whether or not the switch 1 is a switch that outputs a signal in which frequency inversion has occurred, as in step S31 of FIG.

  When it is determined in step S51 that the switch outputs a signal with frequency reversal, in step S52, the control unit 15 performs frequency reversal correction on the signal supplied from the receiving unit 11 thereafter. The demodulator 21 is controlled.

  On the other hand, if it is determined in step S51 that the switch does not output a signal in which frequency inversion occurs, in step S53, the control unit 15 controls the demodulation unit 21 so as not to perform frequency inversion correction thereafter.

  In step S <b> 54, the estimation unit 14 determines broadcast channel candidates based on the spectrum shape represented by the power measured by the spectrum measurement unit 13. The estimation unit 14 outputs information related to each broadcast channel candidate, such as the center frequency, to the control unit 15.

  In step S55, the control unit 15 transmits an ODU_Channel_change command to the switch 1, and sets the IF band so as to receive the first candidate signal of the broadcast channel. For example, the channels are selected as reception target channels in order from the lowest frequency candidate.

  In step S <b> 56, the receiving device 2 sets the first symbol rate candidate in the demodulation unit 21. As described above, when 1 to 45 Msps is used as the symbol rate, for example, among the predetermined number of symbol rates in the range of 1 to 45 Msps, the symbol rate that is most likely to be actually used is the first symbol rate. Set as a candidate for Rate.

  After the IF band is set in step S55 and the symbol rate is set in step S56, reception processing is performed in step S57. That is, the receiving unit 11 extracts the user band 1 signal from the multiplexed signal supplied from the switch 1. Further, the demodulator 21 performs a demodulation process on the user band 1 signal and outputs the equalized signal to the decoder 22. The decoding unit 22 performs error correction decoding on the signal supplied from the demodulation unit 21 and outputs TS to the subsequent stage and outputs a TS Lock signal to the control unit 15 when synchronization can be established. When synchronization cannot be established, the TS Lock signal is not supplied to the control unit 15.

  In step S58, the control unit 15 determines whether synchronization has been established by the reception process.

  If it is determined in step S58 that the synchronization has not been established, in step S59, the control unit 15 determines that the current symbol rate setting value is the actual number of symbols within a predetermined number of symbol rates within the range of 1 to 45 Msps. It is determined whether or not the final symbol rate that is least likely to be used for the current value has been reached.

  If it is determined in step S59 that the final symbol rate has not been reached, in step S60, the control unit 15 sets a next symbol rate candidate, and repeats the processes in and after step S57. In the processing of FIG. 12, for example, among a predetermined number of symbol rates within the range of 1 to 45 Msps, the symbol rates that are most likely to be actually used are sequentially selected, and the reception processing is repeated. .

  On the other hand, if it is determined in step S58 that synchronization has been established because the TS Lock signal has been supplied, in step S61, the control unit 15 stores, for example, current IF band frequency and symbol rate information as channel information. 16 and store.

  After storing the channel information in step S61 or if it is determined in step S59 that the final symbol rate has been reached, in step S62, the control unit 15 determines whether the broadcast channel candidate to be received has reached the final candidate. Determine whether or not.

  If it is determined in step S62 that the final candidate has not been reached, in step S63, the control unit 15 transmits an ODU_Channel_change command to the switch 1 and sets the IF band so as to receive the next candidate signal. After switching the IF band so as to receive the next candidate signal, the processes in and after step S56 are repeated.

  On the other hand, when it determines with having reached the last candidate in step S62, the control part 15 complete | finishes a process.

  Even when the switch 1 for converting the IF band to the user band exists between the satellite antenna and the single cable system, the receiving device 2-1 switches the channel by sequentially switching the IF band received by the switch 1. Scanning can be performed.

  Also, by performing reception processing focusing on candidate channels determined based on spectrum measurement results, channel scanning can be completed more quickly than when receiving a channel in the entire frequency band to be scanned. It becomes possible.

[Modification]
The channel scan described above can also be applied when the satellite antenna and the receiving device are connected by a method other than the single cable method. In other words, a switch serving as a repeater is provided between the satellite antenna and the receiving device, and can be applied to various connection methods in which the frequency band of the received signal of the switch can be controlled from the receiving device.

  In the above description, the input to the switch is the IF signal from the satellite antenna. However, the above description also applies to a case where an RF signal is input and a switch that converts the RF signal into a user band signal and outputs it is provided. Channel scan is applicable. In this case, the receiving device 2-1 performs channel scanning by designating the frequency of the RF band instead of the IF band.

[Configuration example of receiving system]
FIG. 13 is a block diagram illustrating a configuration example of a receiving system to which the receiving device 2-1 in FIG. 6 is applied.

  13 includes a tuner 41, a demodulation / decoding unit 42, a signal processing unit 43, and an output unit 44.

  The tuner 41 receives a signal transmitted via a transmission path such as terrestrial digital broadcasting, satellite digital broadcasting, CATV network, and the Internet, and supplied via the switch 1, and outputs it to the demodulation / decoding unit 42. The receiver 11 of FIG. 6 is included in the tuner 41.

  The demodulation / decoding unit 42 performs transmission path decoding processing including demodulation processing and error correction processing on the signal supplied from the tuner 41, and outputs data obtained by the transmission path decoding processing to the signal processing unit 43. . For example, the signal processing unit 12, the spectrum measurement unit 13, the estimation unit 14, the control unit 15, and the storage unit 16 of FIG. 6 are included in the demodulation / decoding unit 42.

  The signal processing unit 43 appropriately performs signal processing such as expansion processing and descrambling processing on the data obtained by the transmission path decoding processing, and acquires transmission target data.

  The decompression processing by the signal processing unit 43 is performed when data to be transmitted such as images and sounds is compressed on the transmission side using a predetermined method such as MPEG. The descrambling process is performed when data to be transmitted is scrambled on the transmission side. The signal processing unit 43 outputs data to be transmitted obtained by appropriately performing signal processing to the output unit 44.

  When the output unit 44 displays an image based on the data supplied from the signal processing unit 43, the output unit 44 performs processing such as D / A conversion on the data supplied from the signal processing unit 43. The output unit 44 outputs an image signal obtained by performing processing such as D / A conversion to a display provided in the reception system or a display external to the reception system, and displays an image.

  The output unit 44 outputs the data supplied from the signal processing unit 43 to a recording medium inside the receiving system or an external recording medium when recording the data supplied from the signal processing unit 43 on a recording medium. Let me record. The recording medium includes a hard disk, a flash memory, an optical disk, and the like. The external recording medium may be a recording medium connected via a network as well as an external recording medium of the receiving system.

  The receiving system having the configuration shown in FIG. 13 may be configured by hardware such as an IC chip, or may be a component such as a board configured by arranging a plurality of IC chips, or the component. You may make it comprise from the independent apparatus containing.

  Each of the tuner 41, the demodulation / decoding unit 42, the signal processing unit 43, and the output unit 44 can be configured as one independent hardware or software module. Further, a combination of two or more of the tuner 41, the demodulation / decoding unit 42, the signal processing unit 43, and the output unit 44 may be configured as one independent hardware or software module. For example, the tuner 41 and the demodulation / decoding unit 42 may be configured by one piece of hardware, and the signal processing unit 43 and the output unit 44 may be configured by one piece of hardware.

  The receiving system in FIG. 13 can be applied to, for example, a TV that receives a television broadcast as a digital broadcast, a radio receiver that receives a radio broadcast, a recorder device that records the television broadcast, and the like.

[Computer configuration example]
The series of processes described above can be executed by hardware or can be executed by software. When a series of processing is executed by software, a program constituting the software is installed from a program recording medium into a computer incorporated in dedicated hardware or a general-purpose personal computer.

  FIG. 14 is a block diagram illustrating a hardware configuration example of a computer that executes the above-described series of processing by a program.

  A CPU (Central Processing Unit) 51, a ROM (Read Only Memory) 52, and a RAM (Random Access Memory) 53 are connected to each other by a bus 54.

  An input / output interface 55 is further connected to the bus 54. Connected to the input / output interface 55 are an input unit 56 such as a keyboard and a mouse, and an output unit 57 such as a display and a speaker. The input / output interface 55 is connected to a storage unit 58 made up of a hard disk, a non-volatile memory, etc., a communication unit 59 made up of a network interface, etc., and a drive 60 that drives the removable media 61.

  In the computer configured as described above, for example, the CPU 51 loads the program stored in the storage unit 58 to the RAM 53 via the input / output interface 55 and the bus 54 and executes it, thereby executing the above-described series of processing. Is done.

  The program executed by the CPU 51 is recorded in, for example, the removable medium 61 or provided via a wired or wireless transmission medium such as a local area network, the Internet, or digital broadcasting, and is installed in the storage unit 58.

  The program executed by the computer may be a program that is processed in time series in the order described in this specification, or in parallel or at a necessary timing such as when a call is made. It may be a program for processing.

  Embodiments of the present technology are not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present technology.

[Configuration example]
This technology can also take the following composition.

(1)
A controller that receives a signal in a desired frequency band, converts the signal into a signal in a frequency band assigned to the receiving device and outputs the signal, and sequentially changes the frequency band to receive the signal;
And a measuring unit that measures a spectrum of a signal after frequency conversion supplied from the repeater.

(2)
An estimation unit that estimates channel candidates used for broadcasting based on the spectrum;
The said control part makes the said repeater receive the signal of the said candidate channel. The receiving apparatus as described in said (1).

(3)
A signal processing unit that performs signal processing including demodulation and decoding on the frequency-converted signal supplied from the repeater that has received the candidate channel signal;
The receiving apparatus according to (2), further comprising: a storage unit that stores information on the candidate channel that has been able to establish synchronization by the signal processing.

(4)
The information stored in the storage unit includes information on the frequency of the candidate channel. The receiving apparatus according to (3).

(5)
The repeater outputs a signal obtained by frequency-multiplexing a signal in a frequency band assigned to each receiving device on a single coaxial cable to which a plurality of receiving devices including the receiving device itself is connected at a branch destination. Equipment,
The receiving device according to any one of (1) to (4), wherein the control unit transmits a DiSEqC standard command to the repeater to control a reception frequency band.

(6)
The receiving device according to any one of (1) to (5), wherein the signal in the desired frequency band is a signal supplied from an antenna.

(7)
The receiving apparatus according to any one of (1) to (6), wherein the signal in the desired frequency band is an RF signal or an IF signal.

(8)
Receiving a signal in a desired frequency band, receiving a signal by sequentially changing the frequency band to a repeater that converts the signal into a frequency band signal assigned to the receiving device and outputs the signal,
A receiving method including a step of measuring a spectrum of a frequency-converted signal supplied from the repeater.

(9)
Receiving a signal in a desired frequency band, receiving a signal by sequentially changing the frequency band to a repeater that converts the signal into a frequency band signal assigned to the receiving device and outputs the signal,
A program for causing a computer to execute processing including a step of measuring a spectrum of a frequency-converted signal supplied from the repeater.

  2-1 Receiving device, 11 receiving unit, 12 signal processing unit, 13 spectrum measuring unit, 14 estimating unit, 15 control unit, 16 storage unit

Claims (9)

A controller that receives a signal in a desired frequency band, converts the signal into a signal in a frequency band assigned to the receiving device and outputs the signal, and sequentially changes the frequency band to receive the signal;
And a measuring unit that measures a spectrum of a signal after frequency conversion supplied from the repeater. An estimation unit that estimates channel candidates used for broadcasting based on the spectrum;
The receiving device according to claim 1, wherein the control unit causes the repeater to receive a signal of the candidate channel. A signal processing unit that performs signal processing including demodulation and decoding on the frequency-converted signal supplied from the repeater that has received the candidate channel signal;
The receiving apparatus according to claim 2, further comprising: a storage unit that stores information on the candidate channel that has been able to establish synchronization by the signal processing. The receiving apparatus according to claim 3, wherein the information stored in the storage unit includes information on the frequency of the candidate channel. The repeater outputs a signal obtained by frequency-multiplexing a signal in a frequency band assigned to each receiving device on one coaxial cable to which a plurality of receiving devices including the receiving device itself is connected at the branch destination. Equipment,
The receiving device according to claim 1, wherein the control unit transmits a DiSEqC standard command to the repeater to control a reception frequency band. The receiving apparatus according to claim 1, wherein the signal in the desired frequency band is a signal supplied from an antenna. The receiving apparatus according to claim 1, wherein the signal in the desired frequency band is an RF signal or an IF signal. Receiving a signal in a desired frequency band, receiving a signal by sequentially changing the frequency band to a repeater that converts the signal into a frequency band signal assigned to the receiving device and outputs the signal,
A receiving method including a step of measuring a spectrum of a frequency-converted signal supplied from the repeater. Receiving a signal in a desired frequency band, receiving a signal by sequentially changing the frequency band to a repeater that converts the signal into a frequency band signal assigned to the receiving device and outputs the signal,
A program for causing a computer to execute processing including a step of measuring a spectrum of a frequency-converted signal supplied from the repeater.

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