JP4302576B2 - Receiving machine - Google Patents

Description

  The present invention relates to a receiver having a seek function for detecting a broadcast wave by sweeping a tuning frequency in one direction.

Conventionally, there is known a receiver having an auto-tuning function for detecting an adjacent broadcasting station by sweeping a tuning frequency in one direction when a UP / DOWN key is pressed by a user. Among such receivers, there is a receiver that switches the sound source to a CD (compact disc) playback unit during the auto tuning operation and continues the auto tuning operation while outputting the playback sound of the CD (see FIG. For example, see Patent Document 1.) In this receiver, sound source switching is performed when the frequency sweep reaches the third round.
Japanese Patent Laid-Open No. 8-23289 (page 3-7, FIG. 1-5)

  By the way, in the receiver disclosed in Patent Document 1 described above, when the adjacent broadcasting station is not detected, the silent state during the auto-tuning operation of the first and second laps is maintained, so that the output is performed until then. There was a problem that there was a sense of incongruity because the silence output continued for a relatively long time after the radio sound output was suddenly interrupted. The sound source is switched to the CD playback unit during the auto-tuning operation on the third lap. However, if an adjacent broadcasting station is detected in the auto-tuning operation on the third lap after the sound source switching, the CD playback sound is once heard. After being output, it is switched to radio sound again, so the output contents are switched in the order of radio sound, CD playback sound, and radio sound in a short time interval, and it is uncomfortable for the user who is listening to this. Will further increase.

  The present invention has been made in view of such a point, and an object thereof is to provide a receiver capable of reducing a sense of incongruity during frequency sweeping.

  In order to solve the above-described problems, the receiver of the present invention receives a broadcast signal having a set tuning frequency, temporarily stores it in a memory, reads the stored data, and outputs the broadcast content corresponding to the broadcast signal. A receiving means and a broadcast signal detecting means for detecting a broadcast signal whose signal level is equal to or higher than a threshold value by sweeping the tuning frequency, and at the time of frequency sweeping by the broadcast signal detecting means, the broadcast content using the stored data read from the memory Output operation continues. As a result, while searching for other broadcast signals by sweeping the tuning frequency, the output of the broadcast content received before that is continued, so that it is possible to prevent the silence state from continuing and suddenly Since it does not switch to the output sound of another music source, it is possible to reduce a sense of incongruity at the time of frequency sweep.

  Further, it is desirable that the broadcast signal detection means described above stops the tuning frequency sweep when a broadcast signal having a signal level equal to or higher than a threshold value is detected. As a result, it is possible to eliminate the silent state that occurs during auto-tuning using the seek function.

  Further, it is desirable that the broadcast signal detecting means described above stops the tuning frequency sweeping after making a round of the reception frequency band. As a result, it is possible to eliminate a silent state that occurs during auto memory that detects a receivable broadcast signal by making a round of the tuning frequency within the reception frequency band.

  Further, it is desirable that the capacity of the memory described above is equal to or greater than the data amount of the stored data of the broadcast signal that is accumulated during the time when the tuning frequency makes a round of the reception frequency band. Thereby, even when there is no broadcast signal adjacent to the currently received broadcast signal and the frequency sweep is completed, the silent state can be reliably eliminated.

Further, the receiving means described above receives two types of broadcast signals transmitted with a predetermined time difference corresponding to the same tuning frequency and transmits the two types of broadcast signals. It is desirable to provide a memory that is read after a broadcast signal having an early timing is temporarily stored . In a receiver corresponding to such a broadcasting form, it is not necessary to add a memory, so that it is possible to simplify the receiver by reducing the number of additional parts and to reduce the cost associated therewith.

  The above-mentioned two types of broadcast signals are the first broadcast signal that is digitally modulated, one of which is earlier in transmission timing, and the other is the second broadcast signal that is analog-modulated. When the broadcast content can be output for both of the broadcast signals, it is desirable to output the broadcast content corresponding to the first broadcast signal. As a result, it is possible to output broadcast contents based on digitally modulated broadcast signals with good sound quality both during normal operation and during frequency sweeping.

  Hereinafter, a radio receiver according to an embodiment to which the present invention is applied will be described in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration of a radio receiver according to an embodiment. The radio receiver shown in FIG. 1 includes a tuner unit 10, an analog broadcast decoder 20, a digital broadcast decoder 40, a memory 50, an amplifier 60, a speaker 62, a control unit 70, and an operation unit 72. This radio receiver is applied to a broadcast system (IBOC broadcast system) that transmits and receives a broadcast signal having a modulation format for FM in-band on-channel (IBOC) digital audio broadcast (DAB).

  The tuner unit 10 extracts only a predetermined frequency component from various broadcast signals that have reached the antenna 80, converts it into an IF (intermediate frequency) signal having a predetermined frequency band, and outputs it. For example, the tuner unit 10 is configured to include a high frequency amplifier, a mixer circuit, a local oscillator, an IF amplifier, an IF filter, and the like, and only a predetermined frequency component to be received is extracted from a broadcast signal, and frequency conversion is performed. The IF signal after output is output.

  In addition, the tuner unit 10 includes an S meter (signal meter) 12 that detects the reception electric field strength (reception state) of the broadcast signal corresponding to the IF signal. The S meter 12 outputs an S meter signal having a voltage level corresponding to the received electric field intensity, for example, by performing AM detection of the IF signal through an LPF (low pass filter).

  FIG. 2 is a diagram showing frequency allocation of broadcast signals used in the IBOC broadcast system, and shows the output spectrum density of the IF signal corresponding to one broadcast channel output from the tuner unit 10. The horizontal axis of FIG. 2 shows the frequency of the broadcast signal with the center frequency of the IF signal being zero. As shown in FIG. 2, the broadcast signal of this embodiment includes an analog FM broadcast signal as a signal component (first carrier signal) whose spectral density decreases with a predetermined gradient as it deviates from the center frequency, and the analog signal. Digital broadcast signals are included as signal components (second carrier signal) arranged on both sides of the FM broadcast signal, that is, the upper sideband and the lower sideband.

  An analog FM broadcast signal is a broadcast signal generated by performing FM modulation (frequency modulation) on an audio signal. The digital broadcast signal is a broadcast signal generated by digitally modulating an audio signal. The analog FM broadcast signal and the digital broadcast signal are generated by modulating the same audio signal. On the broadcast station side, a predetermined delay amount (for example, about 4 seconds) is generated with respect to the analog FM broadcast signal. ), And an analog FM broadcast signal corresponding to the same content is received with a delay of this delay amount with respect to the digital broadcast signal.

  The analog broadcast decoder 20 performs predetermined demodulation processing based on the analog FM broadcast signal included in the IF signal output from the tuner unit 10 to reproduce and output audio data. The digital broadcast decoder 40 performs predetermined demodulation processing based on the digital broadcast signal included in the IF signal output from the tuner unit 10 to reproduce and output audio data. The demodulated audio data output from the digital broadcast decoder 40 is temporarily stored in the memory 50 and then read out and input to the analog broadcast decoder 20. The capacity of the memory 50 is set so that the tuning frequency is equal to or greater than the data amount of the audio data of the broadcast signal accumulated during the time required to make a round of the reception frequency band.

  In the present embodiment, the analog broadcast decoder 20 includes audio data reproduced using the analog broadcast decoder 20 itself and audio data reproduced using the digital broadcast decoder 40 (accumulated data read from the memory 50). The function to switch is equipped. Normally, digital audio data with good sound quality is selected, and analog audio data is selected instead when digital audio data cannot be selected. In order to perform such switching processing, the audio data output from the digital broadcast decoder 40 is stored in the memory 50 and then input to the analog broadcast decoder 20 once.

  The digital broadcast decoder 40 includes a digital broadcast decoding processing unit 42. The digital broadcast decoding processing unit 42 extracts a digital broadcast signal included in the input IF signal, performs predetermined digital demodulation processing, and outputs audio data.

  As shown in FIG. 1, the analog broadcast decoder 20 includes an analog-to-digital converter (A / D) 21, a bandpass filter (BPF) 22, a detection circuit 23, a noise canceller (NC) 24, a stereo demodulation circuit 25, A soft mute circuit 26, a changeover switch 27, and a digital-analog converter (D / A) 28 are provided.

  The analog-digital converter 21 samples the IF signal input from the tuner unit 10 at a predetermined frequency and converts it into digital data (IF data). The band pass filter 22 extracts a component included in a predetermined band with respect to the center frequency (for example, 10.7 MHz) of IF data. In the present embodiment, two types of bands (narrow band and wide band) can be selectively set. The detection circuit 23 performs a predetermined FM detection process on the IF data after passing through the bandpass filter 22. The noise canceller 24 removes noise components included in the stereo composite data after FM detection.

  The stereo demodulation circuit 25 performs a process of separating L data and R data included in the stereo composite data. The stereo demodulation circuit 25 includes a separation control circuit and a high cut circuit. The separation control circuit performs a blending process for mixing the L data and the R data when the received electric field strength is reduced, and a process for changing the stereo reproduction to monaural reproduction when the received electric field intensity is further reduced. The high cut circuit performs high cut processing to remove the high frequency component when the received electric field strength decreases and the high frequency noise component increases. The soft mute circuit 26 performs a soft mute process for attenuating the output level when the received electric field strength further decreases and the noise component increases.

  The changeover switch 27 selects and outputs either the audio data by analog reproduction output from the soft mute circuit 26 or the audio data by digital reproduction input via the memory 50. Normally, the audio data by digital reproduction is selected and output by the changeover switch 27, but when the digital reproduction is temporarily disabled or the received electric field strength is extremely lowered, the bit error becomes a predetermined value. When digital reproduction becomes difficult due to the increase, the audio data by analog reproduction is selected and output. The digital-analog converter 28 converts the audio data output from the changeover switch 27 into an analog audio signal and outputs the analog audio signal.

  The amplifier 60 shown in FIG. 1 amplifies the audio signal output from the digital-analog converter 28 in the analog broadcast decoder 20 and drives the speaker 62. In FIG. 1, one speaker 62 is shown, but actually two or more speakers are provided for stereo audio signals.

  The control unit 70 controls the entire radio receiver. For example, when various instruction operations are performed by the user using the operation unit 72, the control unit 70 performs a control operation according to the operation content. As a result, a tuning operation for adjusting the tuning frequency to the frequency assigned to the desired broadcast station and an adjustment operation such as volume or sound quality are performed. In particular, in the present embodiment, when the UP key or the DOWN key provided in the operation unit 72 is pressed, the control unit 70 broadcasts that can receive the currently set tuning frequency higher or lower next. It controls the auto-tuning process that scans (sweeps) until the broadcast signal of the station is detected.

  The tuner unit 10, the analog broadcast decoder 20, the digital broadcast decoder 40, the memory 50, the amplifier 60, and the speaker 62 correspond to reception means, and the S meter 12 and the control unit 70 correspond to broadcast signal detection means.

  FIG. 3 is a flowchart showing an operation procedure of auto-tuning processing in the radio receiver of the present embodiment, and when the UP key or DOWN key of the operation unit 72 is pressed while receiving a broadcast signal of any broadcasting station. The auto-tuning operation procedure to be performed is shown.

  While receiving the broadcast signal of any broadcasting station using the radio receiver of this embodiment, the control unit 70 determines whether the UP key or the DOWN key provided in the operation unit 72 is pressed (step). 100). If these keys are not pressed, a negative determination is made and this determination is repeated. When either the UP key or the DOWN key is pressed, an affirmative determination is made in the determination in step 100, and then the control unit 70 sends an instruction to the tuner unit 10 to set the tuning frequency in one direction (UP When the key is pressed, a scanning operation is started (in the direction of increasing the frequency, and when the DOWN key is pressed, in the direction of decreasing the frequency) (step 101).

  Further, the control unit 70 performs control to maintain the connection state of the changeover switch 27 even after the scan operation is started, and outputs the reception data read from the memory 50 to the digital-analog converter 28. Thereby, the reproduction operation of the received signal using the read reception data, that is, the reproduction operation corresponding to the broadcast signal of the broadcast wave received before the start of the scanning operation is continued (step 102).

  In parallel with the scanning operation and the broadcast signal reproduction operation described above, the control unit 70 monitors the signal level of the S meter signal output from the S meter 12, and this signal level becomes equal to or higher than a preset threshold value. It is determined whether or not an adjacent broadcast station is detected (step 103). If not detected, a negative determination is made, and then the control unit 70 determines whether or not the tuning frequency being scanned has made a round of the reception frequency band (step 104). For example, when the UP key is pressed and the scanning operation is performed in a higher frequency direction, when the upper limit frequency is reached, the scanning operation is newly restarted from the lower limit frequency, and the tuning frequency before the start of the scanning operation is reached. When it reaches Similarly, when the DOWN key is pressed and the scan operation is performed in the direction of lower frequency, when the lower limit frequency is reached, the scan operation is newly restarted from the upper limit frequency, and the tuning before the start of the scan operation is performed. It is assumed that when the frequency is reached, a round is taken. Note that such a scanning operation is an example, and when the upper limit frequency is reached during the scanning operation, the scanning operation is continued in a lower direction from the upper limit frequency, and when the lower limit frequency is reached, the scanning frequency is higher than the lower limit frequency. The scanning operation may be continued in the direction, and the cycle may be completed when returning to the tuning frequency before the start of the scanning operation. If the tuning frequency being scanned does not make a round of the reception frequency band, a negative determination is made in the determination in step 104, and the process returns to step 102 and the playback operation using the received data read from the memory 50 is repeated.

  Further, when the tuning frequency being scanned makes a round of the reception frequency band, an affirmative determination is made in the determination of step 104, and the control unit 70 determines whether a broadcast station other than a predetermined notification, for example, a broadcast station that is currently performing a reproduction operation, Notifying that it does not exist using a sound or a display (step 105).

  If a broadcast signal of an adjacent broadcast station is detected during the scanning operation, an affirmative determination is made in the determination of step 103, and then the control unit 70 receives the detected broadcast signal of the adjacent broadcast station. The setting is performed for the tuner unit 10 and the digital broadcast decoder 40 is instructed to start the reproduction process corresponding to the broadcast signal of the adjacent broadcast station. Thereafter, reception processing corresponding to the new broadcasting station is performed (step 106).

  As described above, in the radio receiver according to the present embodiment, while searching for other broadcast signals by scanning the tuning frequency, the output of the broadcast content received before is continued, and thus the silent state continues. Can be prevented, and the output sound of another music source is not suddenly switched at the time of scanning, so that the uncomfortable feeling at the time of frequency scanning can be reduced. In particular, by stopping the scanning of the tuning frequency when a broadcast signal having a signal level equal to or higher than a threshold value is detected, it is possible to eliminate the silent state that occurs during auto tuning.

  Further, by setting the capacity of the memory 50 to be equal to or greater than the data amount of the stored data of the broadcast signal stored during the time when the tuning frequency makes a round of the reception frequency band, there is no broadcast signal adjacent to the currently received broadcast signal. In this case, the silent state can be reliably eliminated even when the frequency sweep is completed.

  In addition, the radio receiver of the present embodiment receives two types of broadcast signals that are transmitted with a predetermined time difference corresponding to the same tuning frequency, and receives these two types of broadcast signals. A memory 50 is provided corresponding to the broadcast signal with the earlier transmission timing. Since it is not necessary to add a new memory to the radio receiver corresponding to such a broadcasting form other than the memory 50 conventionally provided, it is possible to simplify the receiver by reducing the number of additional parts and to reduce the cost associated therewith. become. In particular, these two types of broadcast signals are ones whose transmission timing is early are digitally modulated broadcast signals, and the other are analog-modulated broadcast signals, and output of broadcast contents for both of these two types of broadcast signals. Is possible to output broadcast contents corresponding to digitally modulated broadcast signals, so that broadcast contents based on digitally modulated broadcast signals with good sound quality can be output during both normal operation and frequency sweep. Output becomes possible.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention. In the above-described embodiment, the radio receiver corresponding to IBOC digital audio broadcasting has been described. However, the present invention relates to a receiver corresponding to a broadcasting mode in which only one type of audio signal is included corresponding to one tuning frequency. May be applied. In this case, the reception data corresponding to the broadcast signal is temporarily stored in the memory and then read out to perform the reproduction operation, and the reception data from the memory is continuously read when the tuning frequency is scanned.

  In the above-described embodiment, the tuning frequency is scanned in one direction, and the auto-tuning operation for stopping the scanning operation when a broadcast signal whose signal level is equal to or higher than the threshold value is detected first. The present invention can be applied to an auto memory operation in which the scan operation is continued until one scan is completed and one or a plurality of broadcast stations whose signal level included in the reception frequency band is equal to or higher than the threshold value are detected and registered in the memory. Good. That is, when the user presses the auto memory (auto M) key of the operation unit 72, the control unit 70 scans the tuning frequency until it makes a round and reads from the memory 50 until the scanning operation is completed. You may make it perform the reproduction | regeneration operation | movement using received data. As a result, it is possible to eliminate a silent state that occurs during auto memory that detects a receivable broadcast signal by making a round of the tuning frequency within the reception frequency band.

It is a figure which shows the structure of the radio receiver of one Embodiment. It is a figure which shows the frequency allocation of the broadcast signal used for an IBOC broadcast system. It is a flowchart which shows the operation | movement procedure of the auto tuning process in the radio receiver of this embodiment.

Explanation of symbols

10 Tuner 12 S Meter 20 Analog Broadcast Decoder 27 Changeover Switch 28 Digital-Analog Converter (D / A)
40 Digital Broadcast Decoder 42 Digital Broadcast Decode Processing Unit 50 Memory 60 Amplifier 62 Speaker 70 Control Unit 72 Operation Unit

Claims (5)

Receiving means for receiving a broadcast signal of a set tuning frequency and temporarily storing it in a memory, then reading the stored data and outputting the broadcast content corresponding to the broadcast signal;
Broadcast signal detection means for sweeping the tuning frequency and detecting a broadcast signal having a signal level equal to or higher than a threshold value;
And the capacity of the memory is equal to or greater than the amount of data stored in the broadcast signal accumulated during a time when the tuning frequency makes a round of the reception frequency band, and from the memory during frequency sweeping by the broadcast signal detection means A receiver which continues the output operation of the broadcast contents using the read stored data. In claim 1,
The broadcast signal detecting unit stops sweeping the tuning frequency when a broadcast signal having a signal level equal to or higher than a threshold is detected. In claim 1,
The broadcast signal detecting unit stops sweeping the tuning frequency after making a round of the reception frequency band. In any one of Claims 1-3,
The receiving means receives two types of broadcast signals that are transmitted with a predetermined time difference corresponding to the same tuning frequency, and the transmission timing of these two types of broadcast signals is early. A receiver comprising the memory that is read after a broadcast signal is temporarily stored . In claim 4,
The two types of broadcast signals are one of the first broadcast signals whose transmission timing is early and digitally modulated, and the other is the second broadcast signal which is analog modulated,
The receiver is characterized in that the broadcast content corresponding to the first broadcast signal is output when the broadcast content can be output for both of these two types of broadcast signals.

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