JPH05344015A - Audio equipment including rds receiver - Google Patents

Abstract

PURPOSE:To prevent noise due to reception disturbance when a vehicle enters a reception disturbance area during the reception of a broadcast by an RDS receiver by selecting other music source for a sound output if reception condition is not satisfied. CONSTITUTION:When an automatic tuning function such as a network follow function or the like is operated during reception by a radio data system (RDS) receiver 1a, and when the reception condition is not satisfied over all stations in an AF list due to reception disturbance, the network follow function is continuously executed till any station satisfy the reception condition, and other music sources 20, 21 are sounded automatically for that time. That is, when a vehicle enters a reception disturbance area such as a tunnel, and when the reception disturbance is eliminated after the vehicle passes through the tunnel, an audio signal from the RDS receiver 1a is sounded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio device including a receiver for a radio data system (hereinafter referred to as an RDS receiver).

[0002]

2. Description of the Related Art At the time of program broadcasting of a general broadcasting station, broadcasting-related information such as information related to the program content is transmitted as data by multiplex modulation, and the data is demodulated at the receiving side and desired based on the demodulated data. There is a radio data system (RDS) that enables the selection of the program contents of the above and provides the service to the radio listener.

In this radio data system, F
Outside the frequency band of the M-modulated wave, 57KHz, which is the third harmonic of the 19KHz stereo pilot signal, is used as a sub-carrier, and this sub-carrier is filtered and is related to the broadcasting of program content etc. which is bi-phase coded. A data signal indicating information is amplitude-modulated into a radio data signal, and the amplitude-modulated subcarrier is frequency-modulated as a main carrier for broadcasting. The broadcasting system standard is the European Broadcasting Union (EBU). Has been proposed by.

The radio data signal has a baseband coding structure 104, as can be seen from FIG.
Bits are grouped and repeatedly multiplexed. One group consists of four blocks each having 26 bits, and each block consists of a 16-bit information word and a 10-bit check word. In addition, each group consists of 1 of type 0 to 15 with 4 bits according to the content.
There are 6 types, and two versions A and B are defined for each type (0 to 15).

2A and 2B show formats of the type 0A and 0B groups, respectively. Type 0
In group A (a), block 1 contains 16-bit program identification data (hereinafter referred to as PI data) consisting of a country code, an area code and a program code.
Various codes such as a group type code, a version code (B ₀ ), a traffic information broadcasting station identification (TP) code, and a program content identification (PTY) code are broadcast in block 2, and the same program is broadcast in block 3. Station frequency data (hereinafter abbreviated as AF data) of the network station and broadcast station name data (hereinafter abbreviated as PS data) are arranged in the block 4. On the other hand, in the type 0B group (b), only the contents of the block 3 are different from those in the type 0A group, and the block 3 has P
I data is arranged. That is, the AF data of the network station is transmitted only in the type 0A group, and P
The S data is transmitted in the type 0A and 0B groups. In this way, the radio data signal of the type 0A group also includes AF data of the network station broadcasting the same program as the broadcasting station currently being received. Therefore, at the time of reception, the AF data and PI data obtained by demodulation are captured and stored as an AF list, and when the reception sensitivity of the currently receiving broadcasting station is lowered due to a disturbance such as multipath interference, Based on the stored AF list, other stations in the same network station group are selected, and PI data comparison is performed by a so-called PI check to confirm whether the program received according to the AF list is correct. With the (Network Follow) function, the same program can always be listened to in a good reception state without being affected by disturbance. Furthermore, in the network follow function, since there are stations with different area codes in PI data even in the same network station, regional (Regional) O that ignores the area code during PI check
There are an FF mode and a regional ON mode in which a PI check including the area code is performed. These modes are arbitrarily designated by the user.

FIG. 3 shows a block diagram of an audio apparatus including an RDS receiver having the above-mentioned function as one of audio sources. First, in the RDS receiver 1a,
A desired station is selected by the front end 2 of the FM multiplex broadcast wave received by the antenna 1, converted to an intermediate frequency (IF), and then supplied to the FM detector 4 via the IF amplifier 3. The front end 2 adopts, for example, a PLL synthesizer system using a PLL circuit including a programmable frequency divider, and performs a channel selection operation by controlling a frequency division ratio of the programmable frequency divider by a controller 13 described later. Is becoming The detection output of the FM detector 4 is supplied to an MPX (multiplex) demodulation circuit 5 and, in the case of stereo broadcasting, separated into L (left) and R (right) channel audio signals and reproduced via a muting circuit 18. It is output as an audio signal. The muting circuit 18 is on / off controlled by the controller 13. Further, the detection output of the FM detector 4 passes through the filter 6 to extract the 57 KHz subcarrier amplitude-modulated by the biphase-coded data signal, that is, the radio data signal, and the PLL circuit 7 is extracted.
Demodulated by. This demodulated output is a digital (D) PLL
It is supplied to the circuit 8 and the decoder 9. D-PLL circuit 8
Then, a clock for data demodulation is generated based on the demodulation output of the PLL circuit 7. In the decoder 9, the bi-phase coded data signal which is the demodulation output of the PLL circuit 7 is decoded in synchronization with the clock generated in the D-PLL circuit 8. The lock detection circuit 10 detects a locked state and an unlocked state of the D-PLL circuit 8 and switches and controls the lock range of the PLL circuit 7 and the D-PLL circuit 8 according to the detection output. As shown in FIG. 1, the output data of the decoder 9 is a 104-bit group unit consisting of 4 blocks of 26-bit structure, and is sequentially supplied to the group / block synchronization & error detection circuit 11. The group / block synchronization & error detection circuit 11 establishes block synchronization with the group based on the 10-bit offset word assigned to the 10-bit check word of each block, and also provides 16-bit information based on the check word. Word error detection is performed. Then, the data in which the error has been detected is error-corrected by the error correction circuit 12 in the next stage and then supplied to the controller 13. In addition, I in the IF amplifier 3
The level detection circuit 16 that detects the received signal level (electric field strength) based on the F signal level, and the IF signal level in the IF amplifier 3 is a predetermined level or higher and the detection output of the so-called S curve characteristic in the FM detector 4 is a predetermined level. The level detection circuit 1 is provided with a station detection circuit 17 that detects a receiving station and outputs a station detection signal when it is within the range.
Received signal level detected by 6 and station detection circuit 1
The station detection signal output from 7 is supplied to the controller 13.

The RDS receiver 1a having the above structure
The reproduced audio signal from is supplied to the source selector 19. A CD player (compact disc player) 20 plays the compact disc in response to a performance command signal from the controller 13, and outputs L (left) and R.
The (right) channel stereo reproduction audio signal is supplied to the source selector 19. The tape player 21
Depending on the performance command signal from the controller 13, a compact cassette tape or DAT (Digital Audio Ta
pe) is performed, and stereo reproduction audio signals of the L (left) and R (right) channels are supplied to the source selector 19. The source selector 19 selects one of the reproduced audio signals of the CD player 20, the tape player 21 and the RDS receiver 1a according to the selection signal from the controller 13 and supplies the selected audio signal to the stereo amplifier 22. The stereo amplifier 22 is supplied with L (left) and R
(Right) Amplifies a stereo reproduced audio signal consisting of two channels and outputs the amplified signals to the speakers 23a and 23a, respectively.
supply each to b.

The controller 13 is responsive to an external command from the operation unit 15 for the CD player 20 and the tape player 2.
1, which controls the RDS receiver 1a and the source selector 19 in a centralized manner, and is constituted by a microcomputer or the like. For example, when a performance command of the CD player is issued from the operation unit 15, the controller 13 supplies the source selector 19 with a selection signal for selecting the reproduction audio signal from the CD player 20, and then the performance command to the CD player 20. Supply a signal. By this operation, only the reproduced audio signal from the CD player is supplied to the speakers 23a and 23b via the stereo amplifier 22 and is acoustically output.

Further, the controller 13 has the above-mentioned R
It also controls the operation of the network follow function of the DS receiver 1a. The flowchart of FIG. 4 shows a processing procedure of the network follow function executed by the processor of the controller 13 in the RDS receiver 1a of FIG. In this example, the operation unit 15
In, the regional OFF mode is designated in advance, and the regional ON flag is reset by this designation. In addition, the AF data obtained by demodulating the received broadcast wave is sequentially loaded into the memory 14 from the memory address 0, and the AF list of the same network station as the currently receiving broadcast station has already been created. And

First, the processor fetches AF data and PI data of the broadcast wave currently being received and stores and stores them in a predetermined area of the memory 14 (step S1). Next, the initial address 0 of the AF data is stored in the register N inside the processor (step S2). The processor then registers N
AF data is read from the memory 14 using the contents of the address as an address (step S3), and then the muting circuit 1
Turn on 8 to mute the audio (step S
4) Thereafter, the read AF data is output to the PLL circuit (not shown) in the front end 2 (step S5), and at the same time, the PLL timer of time T ₁ required for the PLL circuit to lock is set (step S5). S6).
The AF data supplied to the PLL circuit is set in the programmable frequency divider in the PLL circuit, and the reception frequency changes from the current reception frequency to another network station frequency until the PLL timer times out. P
After the time-out of the LL timer (step S7), the processor determines whether or not the receiving station exists by monitoring the output of the station detection signal from the station detecting circuit 17 (step S8), and the receiving station exists. If so, the received signal level of the currently receiving network station is fetched from the level detection circuit 16 (step S9), and it is determined whether this received signal level is equal to or higher than a predetermined set level Vs (step S10). .. If it is equal to or higher than the set level Vs, the processor fetches the PI data of the receiving station (step S11), and subsequently determines whether or not the previous regional ON flag is set (step S12).

Since the regional OFF mode is designated in advance, the regional ON flag is reset, and therefore the processor determines whether the captured PI data matches the PI data held in step S1 except for the area code. It is determined whether or not (step S1
3) If they match, the muting circuit 18 is turned off to cancel the audio mute (step S1).
4). As a result, the currently received network station frequency becomes the new reception frequency. In the regional ON mode in which the regional ON flag is set, the processor determines whether the captured PI data matches the PI data held in step S1 including the area code (step S15). If they match, the process proceeds to step S14 to cancel the audio mute. When it is determined in step S8 that there is no receiving station, when it is determined in step S10 that the received signal level is lower than the set level Vs, or step S1
If the PI data is determined not to match in S3 and S15, the processor reads the content of the register N and determines whether it exceeds the final address of the AF list (step S16). If it does not exceed the final address, the content of register N plus 1 is overwritten and stored in register N (step S17), and then the process returns to step S3 to repeat the above-described processing. At this time, if the content of the register N exceeds the final address of the AF list in step S16, the processor reads the original AF data held in step S1 (step S18) and sends the read AF data to the PLL circuit. It outputs (step S19) and simultaneously sets the PLL timer (step S20). Then, after the time of the PLL timer is up (step S21), the audio mute is released (step S14). As a result, the received frequency has returned to the original frequency of the receiving station.

However, in the audio device including the above-mentioned conventional RDS receiver, in the network follow operation of the RDS receiver, if the receiving condition is not satisfied over all the stations in the AF list, the original receiving station Since the tuning is fixed at the frequency, for example, when a car approaches a reception obstruction area such as a tunnel, it will output the broadcast of the original receiving station as sound regardless of whether reception is possible,
Since noise due to reception interference is heard, there is a problem in that it is not preferable.

[0013]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and even when a car approaches a reception obstruction area such as a tunnel while receiving a broadcast by an RDS receiver, An object of the present invention is to provide an audio device including an RDS receiver in which unpleasant noise due to interference is not acoustically output.

[0014]

According to the present invention, there is provided a list of receiving stations composed of different receiving frequencies for broadcasting the same broadcast content as that of the current receiving frequency, which is preset according to a receiving state of a broadcast wave at the current receiving frequency. An audio device including an RDS receiver having a network follow function for selecting 1 to receive a broadcast wave according to the reception frequency of the selected receiving station, wherein the audio device plays a music source and outputs an audio signal. Playing means, receiving station detecting means for detecting the presence of receiving stations that can be received from all receiving stations set in the frequency list, and when the receiving station detecting means does not detect the presence of receiving stations. RD
S The audio output selecting means for selecting the audio signal from the at least one playing means instead of the audio signal from the S receiver as an acoustic output, and the presence of the receiving station is not detected by the receiving station detecting means. Muting means for muting the audio signal from the RDS receiver.

[0015]

In the audio device including the RDS receiver according to the present invention, when the receiving condition is not satisfied over all the stations in the AF list in the automatic tuning operation such as the network follow operation, the audio output is transmitted to another music source. Switch. At this time, the network follow operation is continued, and when the reception condition is satisfied, the acoustic output is switched to the RDS receiver.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 5 shows a flow chart of an audio device including the RDS receiver of the present invention implemented in the device shown in the block diagram of FIG. In this example, the source selector 19 is set by the operation unit 15 so that the audio signal from the RDS receiver 1a is acoustically output by the speakers 23a and 23b. Machine 1
It is assumed that the regional OFF mode of a is designated and the regional ON flag is reset by this designation. Further, it is assumed that an AF list of the same network station as the broadcasting station currently being received has already been created in the memory 14 in which AF data obtained by demodulating the received broadcast wave is sequentially fetched from memory address 0. To do.

First, the processor of the controller 13 takes in AF data and PI data of the broadcast wave currently being received and stores them in a predetermined area of the memory 14 (step S).
1). Next, the initial address 0 of the AF data is stored in the register N inside the processor (step S2). Next, the processor uses the contents of the register N as an address in the memory 14
The AF data is read from (step S3), the muting circuit 18 is turned on and the audio is muted (step S4), and the read AF data is output to the PLL circuit (not shown) in the front end 2. (Step S5), and at the same time, the PLL timer of time T ₁ required for locking the PLL circuit is set (step S6). The AF data supplied to the PLL circuit is set in the programmable frequency divider in the PLL circuit,
During the period until the PLL timer times out, the reception frequency changes from the current reception frequency to another network station frequency. After the time-up of the PLL timer (step S7), the processor determines whether or not the receiving station exists by monitoring the output of the station detection signal from the station detecting circuit 17 (step S8), and the receiving station exists. If so, the received signal level of the network station currently being received is fetched from the level detection circuit 16 (step S
9) It is determined whether or not the received signal level is equal to or higher than a predetermined set level Vs (step S10). If it is equal to or higher than the set level Vs, the processor determines the PI of the receiving station.
The data is fetched (step S11), and then it is determined whether or not the previous regional ON flag is set (step S12).

Since the regional OFF mode is designated in advance, the regional ON flag is reset, and therefore the processor determines whether the captured PI data and the PI data held in step S1 match except for the area code. It is determined whether or not (step S1
3) If they match, the source selector 1 is set so that the audio signal from the RDS receiver 1a is acoustically output.
A selection signal is supplied to 9 (step S50), and the muting circuit 18 is turned off to cancel the audio mute (step S14). As a result, the currently received network station frequency becomes the new reception frequency, and RD
The audio signal from the S receiver 1a is acoustically output.
In the regional ON mode in which the regional ON flag is set, the processor determines whether the captured PI data matches the PI data held in step S1 including the area code (step S15). If they match, a selection signal is supplied to the source selector 19 so that the audio signal from the RDS receiver 1a is acoustically output (step S50),
The muting circuit 18 is turned off to cancel the audio mute (step S14). If it is determined in step S8 that there is no receiving station, in step S10 it is determined that the received signal level is lower than the set level Vs, or when it is determined in steps S13 and S15 that the PI data do not match, the processor The contents of the register N are read and it is judged whether or not it exceeds the final address of the AF list (step S16).
If the last address in the list is not exceeded, register N
The value obtained by adding 1 to the content of (1) is overwritten and stored in the register N (step S17), and then the process returns to step S3 to repeat the above-described processing. At this time, if the content of the register N exceeds the final address of the AF list in step S16, the processor is in a playable state (CD, compact cassette or DAT is loaded). State)
Is detected by the playable flag signal supplied from the CD player 20 and the tape player 21 (step S51). As a result, it is determined that neither the CD player 20 nor the tape player 21 is in the playable state. If so, the process returns to step S2 and the above-described processing is repeated. When it is determined that either the CD player 20 or the tape player 21 is in the playable state, the selection signal is sent to the source selector 19 so that the reproduced audio signal in the playable state is acoustically output. Supply (step S52). Next, the processor supplies a performance command signal to the player in the playable state (step S53), and returns to step S2 to repeat the above-described processing.

According to the audio apparatus including the RDS receiver having the above-mentioned configuration, when the network follow function is activated during the reception of the broadcast by the RDS receiver, the reception condition is spread over all the stations in the AF list due to the reception interference. When the condition is not satisfied, the network follow function is continued. During this time, the audio signal from the RDS receiver is muted because the network follow function is activated. At this time, when a music playing device such as a CD player and a tape player connected to the audio device is in a playable state, the music playing device is put into a playing state, and this music is replaced with the audio signal from the RDS receiver. A switching operation is performed so as to acoustically output the audio signal from the playing device. After that, if any station in the AF list satisfies the reception condition by the network follow function, a switching operation is performed so that the audio signal from the RDS receiver is acoustically output instead of the audio signal from the music playing device. ..

[0020]

As described above, the RD according to the present invention
The audio device including the S receiver did not satisfy the reception condition across all stations in the AF list due to reception interference when the automatic tuning function such as the network follow function was activated while the broadcast was being received by the RDS receiver. At this time, the network follow function is continuously performed until any station in the AF list satisfies the reception condition, and during this period, another music source is automatically output as sound.

Therefore, when the car approaches a reception obstruction area such as a tunnel while receiving the broadcast by the RDS receiver, another music source is automatically output as sound, and the car exits the tunnel. RDS when there is no interference
Since the audio signal from the receiver is automatically output as a sound, it is preferable that the user does not hear unpleasant noise due to reception interference and that a good sound output is always provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a baseband coding structure of radio data.

FIG. 2 is a diagram showing formats of group types 0A (a) and 0B (b).

FIG. 3 is a block diagram of an audio device that includes an RDS receiver.

FIG. 4 is a flowchart showing a network follow operation of a conventional RDS receiver.

FIG. 5 is a flow chart diagram illustrating operation of an audio device including an RDS receiver according to the present invention.

[Explanation of symbols for main parts]

 1a RDS Receiver 13 Controller 19 Source Selector

Claims (1)

[Claims] 1. A 1 is selected from a reception station group list consisting of different reception frequencies which broadcast the same broadcast content as the broadcast of the current reception frequency which is preset according to the reception state of the broadcast wave at the current reception frequency. An audio device including an RDS receiver having a network follow function for receiving a broadcast wave at the reception frequency of the selected receiving station, comprising at least one playing means for playing a music source and outputting an audio signal. , A receiving station detecting means for detecting the presence of a receiving station that can be received from all receiving stations set in the frequency list, and an RDS receiver when the presence of the receiving station is not detected by the receiving station detecting means Sound output selecting means for selecting the audio signal from the at least one playing means as a sound output instead of the audio signal of Audio apparatus comprising a RDS receiver characterized by having a Myuteingu means for Myuteingu the audio signal from the RDS receiver when the presence of the receiving station is not detected by the signal station detection means.