JP2007306458A - Receiver and electronic apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the chancel search time by a receiver. <P>SOLUTION: The receiver 12 comprises a receiving unit 14 receiving broadcast signals on a plurality of channels, a detector 16 for detecting the receiving intensity of the broadcast signals received by the receiving unit 14, and a controller 17 for controlling the receiving unit 14 based on the receiving intensity of the broadcast signals detected by the detector 16. The controller 17 controls the receiving unit 14 to receive broadcast signals on the plurality of channels at the channel search, and to individually receive broadcast signals at the receiving unit 14 on a specific channel among the plurality of channels when deciding that the receiving intensity of the broadcast signals detected by the detector 16 exceeds a specified level. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a receiving apparatus that receives a broadcast signal and an electronic apparatus using the receiving apparatus.

  A conventional receiving apparatus will be described below with reference to FIG. FIG. 10 is a block diagram of a conventional electronic device. In FIG. 10, the receiving device 1 includes a receiving unit 3 that receives a broadcast signal via an antenna 2, and a demodulating unit 4 connected to the output side of the receiving unit 3. The receiving device 1 also includes a detection unit 5 that detects the reception intensity of the broadcast signal received by the reception unit 3 and a control unit 6 that controls the reception unit 3 based on the reception intensity of the broadcast signal detected by the detection unit 5. And a storage unit 7 connected to the control unit 6. The electronic device 8 equipped with the receiving device 1 includes a signal processing unit 9 connected to the output side of the demodulation unit 4, a reproduction unit 10 connected to the output side of the signal processing unit 9, and a control unit 6. And an input unit 11 connected to the.

  Next, the operation at the time of channel search of the conventional receiving apparatus 1 will be described.

  When a user inputs a channel search instruction using the input unit 11, the control unit 6 detects a signal from the input unit 11 and sets the receiving unit 3 to the first channel. In response to this, the receiving unit 3 selects a channel N broadcast signal among the plurality of channels of broadcast signals received by the antenna 2 and outputs the channel N broadcast signal to the demodulation unit 4. The detection unit 5 detects the reception intensity of the broadcast signal of the channel N from the reception unit 3, and outputs the reception intensity information of the broadcast signal of the first channel to the control unit 6. In response to this, the control unit 6 compares the reception intensity information of the broadcast signal of the channel N from the detection unit 5 with a predetermined level. If the control unit 6 determines that the reception intensity of the broadcast signal of channel N received by the reception unit 3 is less than a predetermined level as a result of the comparison, information indicating that the broadcast signal of channel N cannot be received is displayed. Record in the storage unit 7. On the other hand, when the control unit 6 determines that the reception intensity of the broadcast signal of channel N received by the reception unit 3 is equal to or higher than a predetermined level as a result of the comparison, the control unit 6 demodulates the broadcast signal of channel N selected by the reception unit 3. The unit 4 demodulates. Further, the control unit 6 reads the broadcast information included in the channel N broadcast signal demodulated by the demodulation unit 4 and determines whether or not the channel N broadcast signal is a regular broadcast signal. As a result of this determination, when the broadcast signal of channel N is not a regular broadcast signal, the control unit 6 records information that the broadcast signal of channel N cannot be received in the storage unit 7. On the other hand, if the result of determination is that the broadcast signal of channel N is a regular broadcast signal, the control unit 6 records in the storage unit 7 information that the broadcast signal of channel N can be received.

  Then, the control unit 6 performs the above process on all channels and creates a channel list in the storage unit 7. With this process, once the user performs a channel search, the user can efficiently select a desired channel without performing a channel search again.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP 2004-179928 A

  The conventional receiving apparatus has a problem that a long time is required for channel search because the detection processing by the detection unit 5 is individually performed for each channel.

  Therefore, an object of the present invention is to shorten the time for channel search by the receiving apparatus.

  In order to achieve this object, the receiving apparatus of the present invention includes a receiving unit capable of receiving a broadcast signal of a plurality of channels, a detecting unit for detecting the reception intensity of the broadcast signal received by the receiving unit, and the detecting unit And a control unit that controls the receiving unit based on the received intensity of the broadcast signal. The control unit causes the reception unit to receive a broadcast signal of a plurality of channels at the time of channel search, and determines that the reception intensity of the broadcast signal of the plurality of channels detected by the detection unit is equal to or higher than the predetermined level. Of the signals, broadcast signals of specific channels are individually received by the receiving unit.

  As described above, the receiving apparatus of the present invention can shorten the channel search time.

(Embodiment 1)
Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an electronic device according to Embodiment 1 of the present invention.

  In FIG. 1, the receiving device 12 includes a receiving unit 14 that receives a broadcast signal via an antenna 13, and a demodulating unit 15 connected to the output side of the receiving unit 14. In addition, the reception device 12 includes a detection unit 16 that detects the reception intensity of the broadcast signal received by the reception unit 14 and a control unit 17 that controls the reception unit 14 based on the reception intensity of the broadcast signal detected by the detection unit 16. And a storage unit 18 connected to the control unit 17. The electronic device 19 equipped with the receiving device 12 includes a signal processing unit 20 connected to the output side of the demodulation unit 15, a reproduction unit 21 connected to the output side of the signal processing unit 20, and the control unit 17. And an input unit 22 connected to the.

  The receiving unit 14 receives, for example, a terrestrial digital broadcast signal via the antenna 13. The receiving unit 14 includes a filter 23 that is connected to the output side of the antenna 13 and allows a signal in a band wider than the frequency interval of adjacent channels to pass therethrough, and an amplifying unit 24 that is connected to the output side of the filter 23. . The receiving unit 14 is controlled by the control unit 17 to receive a local signal generating unit 25 that oscillates a local signal, and a local signal from the local signal generating unit 25. And a phase shift unit 26 that outputs a local signal having a phase difference of 90 degrees with respect to the local signal. Further, the receiving unit 14 uses the one local signal from the phase shift unit 26 to convert one output signal from the amplification unit 24 into an IF signal, and the other from the phase shift unit 26. The second mixing unit 28 converts the other output signal from the amplification unit 24 into an IF signal using the local signal. Furthermore, the receiving unit 14 includes a first phase shift filter 29 including a polyphase filter connected to the output side of the first mixing unit 27 and a polyphase filter connected to the output side of the second mixing unit 28. And a second phase shift filter 30. Furthermore, the receiving unit 14 includes a combining unit 31 that combines the IF signal from the first phase shift filter 29 and the IF signal from the second phase shift filter 30. In addition, the receiving unit 14 includes a switch 10 connected between the amplifying unit 24 and the second mixing unit 28. The phase shift unit 26, the first mixing unit 27, the second mixing unit 28, the first phase shift filter 29, the second phase shift filter 30, and the combining unit 31 constitute an image rejection mixing unit.

  Next, the operation of the receiving unit 14 during normal reception of a broadcast signal and during channel search will be described.

  First, the operation of the receiving unit 14 during normal reception of a broadcast signal will be described with reference to FIG. In FIG. 2, the horizontal axis indicates the frequency, and the frequency band of channel N and the frequency band of channel N + 1 are shown.

  At the time of normal reception, the control unit 17 sets the signal pass band of the filter 23 to the frequency band 32 including the desired frequency ωrf in order to cause the demodulation unit 15 to demodulate the predetermined segment of the desired frequency ωrf in the channel N. The oscillation frequency of the generator 25 is set to a frequency ωlo that is higher than the desired frequency ωrf by an intermediate frequency. As a result, a signal (cosωrft) in the frequency band 32 is output from the filter 23, and this signal is supplied to the first mixing unit 27 and the second mixing unit 28. The first mixing unit 27 frequency-converts the (cos ωrft) signal from the filter 23 into an IF signal in the frequency ωif band using the local signal (cos ωlot) having the frequency ωlo, and the second mixing unit 28 outputs (cos ωrft) from the filter 23. ) Is frequency-converted to an IF signal in the frequency ωif band using a local signal (sin ωlot) having a frequency ωlo. At this time, in the first mixing unit 27, the signal in the frequency ωim band (cos ωimt) that has not been completely attenuated in the filter 23 is frequency-converted into the image interference signal in the frequency ωif band by the local signal (cos ωlot) at the frequency ωlo. That is, the output signal of the first mixing unit 27 becomes a desired signal represented by (Equation 1) and an image disturbance signal represented by (Equation 2). Similarly, the output signal of the second mixing unit 28 becomes a desired signal represented by (Equation 3) and an image disturbance signal represented by (Equation 4).

Then, for example, the output signal of the first mixing unit 27 is passed through a first phase shift filter 29 that is a low-pass filter having a phase shift of 0 degree, and the output signal of the second mixing unit 28 is passed through a low phase shift of 90 degrees. When passing through the second phase shift filter 30 which is a pass filter, the high-frequency component is attenuated, (Equation 1) is 1/2 cosω _if t, (Equation 2) is 1/2 cosω _if t, (Equation 3) is 1 / 2 cos ω _if t, (Equation 4) becomes −½ cos ω _if t. That is, the output signal of the first phase-shift filter 29, (1 / 2cosω _if t) becomes an interference signal represented by the desired signal and the (1 / 2cosω _if t) represented by the output signal of the second phase-shift filter 30 , (1/2 cos ω _if t) and a desired signal indicated by (−1/2 cos ω _if t), and the output signal of the combining unit 31 is a desired signal indicated by (cos ω _if t).

  As described above, the receiving unit 14 according to the first embodiment can supply a high-quality desired signal to the demodulating unit 15 by attenuating the image interference signal when the broadcast signal is normally received.

  Next, the operation of the receiving unit 14 at the time of channel search will be described with reference to FIGS. In FIG. 3, the oscillation frequency of the local signal generator 25 at the time of channel search is indicated by an arrow. As shown in FIG. 3, the control unit 17 sets the oscillation frequency of the local signal generation unit 25 to a frequency between the channel N and the channel N + 1 at the time of channel search, so that the reception signal of the two channels is transmitted to the reception unit 14. Are received simultaneously.

  Next, the operation of the receiving device 12 during channel search will be described with reference to FIG.

  When receiving a channel search instruction from the user via the input unit 22, the control unit 17 sets the signal pass band of the filter 23 to the frequency ωrfs of the channel N and the channel N + 1 shown in FIG. Is set to a frequency band 33 including both of the frequencies ωims (S1). The width of the frequency band 33 is substantially equal to the width of the frequency band 32 of the broadcast signal that the filter 23 passes during normal reception. The control unit 17 sets the oscillation frequency of the local signal generation unit 25 to a frequency ωlos between the channel N and the channel N + 1. Furthermore, the power supplied to the second mixing unit 28 and the second phase shift filter 30 is cut off by turning off the switch 10 of the receiving unit 14.

  As a result, the output signal of the first mixing unit 27 becomes the signal of the channel N represented by (Equation 1) and the signal of the channel N + 1 represented by (Equation 2).

When the output signals of these mixing sections are passed through the first phase shift filter 29 which is a low-pass filter having a phase shift of 0 degree, the high frequency component is attenuated, and (Equation 5) is 1/2 cosω _if t, (Equation 6 ) Is 1/2 cos ω _if t. That is, the output signal from the combining unit 31, (1 / 2cosω _if t) _IF signal channel N has been frequency converted represented by the (1 / 2cosω _if t) _IF signal channel N + 1 is frequency-converted represented by It becomes.

  As described above, at the time of channel search, the image rejection signal removal function of the image rejection mixing unit is turned off by turning on one of the first mixing unit 27 and the second mixing unit 28 and turning off the other function. Can be.

  Thereby, in S2, it can be detected whether there is a broadcast signal for both channel N and channel N + 1, and the power consumption of receiving apparatus 12 can be reduced.

  Then, the control unit 17 compares the reception intensity of the broadcast signals of channel N and channel N + 1 with a predetermined level set in advance (S2). Then, whether or not the reception intensity of the broadcast signals of channel N and channel N + 1 is equal to or higher than a predetermined level is recorded in the storage unit 18 (S3). Further, it is determined whether or not all channels have been searched (S4). If all channels have not been searched, the process returns to S1, and the control unit 17 sets the signal passband of the filter 23 to the frequency of the channel N + 2 and the channel N + 3. And the oscillation frequency of the local signal generator 25 is set to a frequency between the channels N + 2 and N + 3. And the control part 17 repeats the process of S1 to S4 about the channel N + 2 and the channel N + 3. In this way, the processing from S1 to S4 is repeated for all channels. If it is determined in S4 that all channels have been searched, the control unit 17 performs channel search for each channel individually for each channel for which the reception strength is determined to be equal to or higher than a predetermined level in S2. Processing is performed (S5, S6). Specifically, when it is determined in S2 that the reception intensity of the broadcast signal of channel N or channel N + 1 is equal to or higher than a predetermined level, the control unit 17 sets the signal pass band of the filter 23 as shown in FIG. A part of the frequency band 34 of the channel N is set, and the oscillation frequency of the local signal generator 25 is set to a frequency ωloa separated from the desired frequency by an intermediate frequency. Then, whether or not the reception intensity of the broadcast signal of channel N is higher than a predetermined level is recorded in the storage unit 18 (S7). Further, it is determined whether or not the search is performed for all the channels for which the reception intensity is determined to be equal to or higher than the predetermined level in S2 (S8). If all the channels are not searched as a result of the determination, the process returns to S5, and the control unit 17 sets the signal pass band of the filter 23 to a part of the frequency band 35 of the frequency band of the channel N + 1, and the local signal generation unit 25 Is set to a frequency ωlob separated from the desired frequency band by an intermediate frequency. And the control part 17 repeats the process of S5 to S8 about the channel N + 1. As described above, the processes from S5 to S8 are repeated for all the channels for which the reception intensity is determined to be equal to or higher than the predetermined level in S2. If it is determined in S8 that all channels have been searched, the control unit 17 ends the channel search.

  In this way, channel search time can be shortened by performing a search for every two channels first, and then performing a channel-by-channel search for channels whose reception intensity is a predetermined level or higher.

  Note that the control unit 17 causes the demodulation unit 15 to demodulate the broadcast signal of the channel whose reception intensity is determined to be equal to or higher than the predetermined level in S6 of FIG. 4, and broadcasts the TMCC information or the like included in the demodulated broadcast signal. Information may be read to determine whether the broadcast signal of this channel is a regular broadcast signal. If the result of this determination is that this broadcast signal is not a regular broadcast signal, the control unit 17 records information in the storage unit 18 that the broadcast signal of this channel cannot be received. On the other hand, when the broadcast signal of this channel is a regular broadcast signal, information that the broadcast signal of this channel is receivable is recorded in the storage unit 18. As a result, it is possible to more accurately determine whether or not each channel is capable of receiving. Note that when the broadcast information is read from the signal demodulated by the demodulator 15, the switch 10 is preferably turned on. As a result, since the image interference signal can be removed from the signal output from the combining unit 31, it is possible to determine whether each channel can be received more accurately.

(Embodiment 2)
A receiving apparatus according to Embodiment 2 of the present invention will be described with reference to FIG. The difference between the second embodiment and the first embodiment is that the signal from the first phase shift filter 29 and the second phase shift filter 30 before the detection unit 16 is synthesized by the synthesis unit 31 in S2 of FIG. The function of the image rejection mixing unit is turned off by detecting either one of the signals from. Other operations are the same as those in the first embodiment. The detector 16 may detect the signal strength between the first mixing unit 27 and the first phase shift filter 29 or the signal strength between the second mixing unit 28 and the second phase shift filter 30. .

  Since the receiving device 14 of the second embodiment does not have the switch 10 of the first embodiment, it is possible to suppress the deterioration of the intensity of the broadcast signal due to the switch in the circuit on the second mixing unit 28 side during normal reception. In this way, channel search time can be shortened by performing a search for every two channels first, and then performing a channel-by-channel search for channels whose reception intensity is a predetermined level or higher.

(Embodiment 3)
A third embodiment of the present invention will be described with reference to FIG. The difference between the third embodiment and the first embodiment is that a signal from the first mixing unit 27 and a signal from the second mixing unit 28 are selectively input, and the input signals are input to the first phase shifter. A signal path selection unit 36 that selectively outputs to the filter 29 and the second phase shift filter 30 is provided.

  During normal reception of a broadcast signal, the signal path selection unit 36 connects the output of the first mixing unit 27 to the input of the first phase shift filter 29 and the output of the second mixing unit 28 as the second phase shift filter 30. Connected to the input. As a result, the function of the image rejection mixing unit is turned on, the image interference signal is removed, and a high-quality desired signal can be supplied to the demodulation unit 15.

  On the other hand, the operation at the time of channel search will be described with reference to FIG.

  When receiving a channel search instruction from the user, the control unit 17 sets to receive both the frequency ωifs of the channel N and the frequency ωims of the channel N + 1 as in the first embodiment (S1). However, unlike the first embodiment, the control unit 17 causes the second mixing unit 28 and the second phase shift filter 30 to function. Further, the control unit 17 sets the signal path selection unit 36 in the same manner as in the normal reception. That is, the control unit 17 connects the output of the first mixing unit 27 to the input of the first phase shift filter 29 and connects the output of the second mixing unit 28 to the input of the second phase shift filter 30. Accordingly, the broadcast signal of channel N + 1 is attenuated by turning on the image disturbance signal attenuation function of the image rejection mixing unit, and the output signal of the combining unit 31 is a signal obtained by frequency-converting only the signal of channel N. When the detector 16 detects the output signal of the synthesizer 31, the reception intensity of the channel N is detected (S2a). Further, the control unit 17 compares the reception intensity of the broadcast signal of channel N with a predetermined level set in advance, and whether or not the reception intensity of the broadcast signal of channel N is equal to or higher than the predetermined level in S3 is stored in the storage unit 18. It is recorded (S3a).

  Next, the control unit 17 controls the signal path selection unit 36 to connect the output of the first mixing unit 27 to the input of the second phase shift filter 30 and to connect the output of the second mixing unit 28 to the first phase shift filter. Connect to 29 inputs. As a result, the broadcast signal of channel N is attenuated, and the output signal of the combining unit 31 is a signal obtained by frequency-converting only the signal of channel N + 1. And if the detection part 16 detects the output signal of the synthetic | combination part 31, the reception intensity | strength of the channel N + 1 will be detected (S2b). Further, the control unit 17 compares the reception intensity of the broadcast signal of channel N + 1 with a predetermined level set in advance, and whether or not the reception intensity of the broadcast signal of channel N + 1 is equal to or higher than the predetermined level in S3 is stored in the storage unit 18. It is recorded (S3b).

  As described above, the receiving apparatus 12 according to the third embodiment determines whether or not the reception intensity of the broadcast signal of the channel N and the reception intensity of the channel N + 1 are equal to or higher than a predetermined level with one frequency setting of the local signal generation unit 25. It becomes possible to judge individually. As a result, the receiving apparatus of the third embodiment can reduce the channel search time because the lockup time in the local signal generator 25 that requires a long time is reduced compared to the first embodiment.

  The receiving device of the present invention can shorten the channel search time during channel search, and can be used for electronic devices such as portable terminals and in-vehicle receiving devices.

1 is a block diagram of an electronic device according to Embodiment 1 of the present invention. Frequency relationship diagram for explaining the operation of the electronic device Frequency relationship diagram for explaining the operation of the electronic device Operation flow chart for channel search of the same electronic device Frequency relationship diagram for explaining the operation of the electronic device Frequency relationship diagram for explaining the operation of the electronic device The block diagram of the electronic device in Embodiment 2 of this invention The block diagram of the electronic device in Embodiment 3 of this invention Operation flow chart for channel search of the same electronic device Block diagram of conventional electronic equipment

Explanation of symbols

DESCRIPTION OF SYMBOLS 13 Antenna 14 Receiving part 15 Demodulation part 16 Detection part 17 Control part 18 Storage part 19 Electronic device 20 Signal processing part 21 Playback part 23 Filter 24 Amplification part 25 Local signal generation part 26 Phase shift part 27 1st mixing part 28 2nd mixing Unit 29 first phase shift filter 30 second phase shift filter 31 combining unit

Claims (10)

A reception unit capable of receiving a broadcast signal of a plurality of channels, a detection unit for detecting the reception intensity of the broadcast signal received by the reception unit, and the reception unit based on the reception intensity of the broadcast signal detected by the detection unit A control unit for controlling,
The control unit causes the receiving unit to receive the broadcast signals of the plurality of channels at the time of channel search, and determines that the reception intensity of the broadcast signals of the plurality of channels detected by the detection unit is equal to or higher than the predetermined level. A receiving device that causes a receiving unit to individually receive a broadcast signal of a specific channel among broadcast signals of a channel. The receiving device according to claim 1, wherein the receiving unit includes a filter that is connected to an input side of the detection unit and allows a broadcast signal having a wider band than a frequency interval between adjacent channels to pass. The receiving unit has an image rejection mixing unit that converts the received broadcast signal into an IF signal,
An image rejection mixing unit includes a first mixing unit and a second mixing unit that convert the received broadcast signal into an IF signal by receiving local signals having a phase difference from each other, and an IF signal from the first mixing unit. And a phase shift filter for phase shifting at least one of the IF signals from the second mixing unit,
The receiving device according to claim 1, wherein one of the first mixing unit and the second mixing unit is caused to function during the channel search. The receiving unit has an image rejection mixing unit that converts the received broadcast signal into an IF signal,
The image rejection mixing unit includes a first mixing unit and a second mixing unit that convert the received broadcast signal into an IF signal by receiving local signals having a phase difference from each other, and an IF from the first mixing unit. A first phase shift filter for phase shifting the signal, a second phase shift filter for phase shifting the IF signal from the second mixing unit, an IF signal from the first phase shift filter, and a second phase shift filter A synthesis unit that synthesizes the IF signal;
2. The reception according to claim 1, wherein, at the time of the channel search, the detection unit detects one of a signal from the first mixing unit and a signal from the second mixing unit before being combined by the combining unit. apparatus. The receiving unit has an image rejection mixing unit that converts the received broadcast signal into an IF signal,
The image rejection mixing unit includes a first mixing unit and a second mixing unit that convert the received broadcast signal into an IF signal by receiving local signals having a phase difference from each other, and an IF from the first mixing unit. A first phase shift filter for phase shifting a signal, a second phase shift filter for phase shifting an IF signal from the second mixing unit, a signal from the first mixing unit, and a signal from the second mixing unit. The receiving apparatus according to claim 1, further comprising: a signal path selection unit that selectively inputs and selectively outputs the input IF signals to the first phase shift filter and the second phase shift filter. The receiving apparatus according to claim 2, wherein the phase shift filter is a polyphase filter. The receiving device according to claim 1, wherein the receiving unit receives at least a part of a frequency band corresponding to each channel. The receiving apparatus according to claim 1, wherein the frequency bandwidth of the broadcast signal received by the receiving unit during the channel search is substantially equal to the frequency bandwidth of the broadcast signal received by the receiving unit during normal reception. A reception unit capable of receiving a broadcast signal of a plurality of channels, a detection unit for detecting the reception intensity of the broadcast signal received by the reception unit, and the reception unit based on the reception intensity of the broadcast signal detected by the detection unit A control unit for controlling, a demodulating unit connected to the output side of the receiving unit, a signal processing unit connected to the output side of the demodulating unit, and a reproducing unit connected to the output side of the signal processing unit Prepared,
The control unit causes the receiving unit to receive the broadcast signals of the plurality of channels at the time of channel search, and determines that the reception intensity of the broadcast signals of the plurality of channels detected by the detection unit is equal to or higher than the predetermined level. An electronic device that causes a receiving unit to individually receive a broadcast signal of a specific channel among broadcast signals of a channel. The electronic device according to claim 9, wherein the control unit reads broadcast information included in a broadcast signal demodulated by the demodulation unit, and determines whether the broadcast signal is a regular broadcast signal.

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