JPS647694B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an on-vehicle radio receiver.

Conventionally, in-vehicle radio receivers have generally been equipped with a memory device for storing reception stations and quickly selecting a desired station for ease of operation. This kind of memory method is
There has been a shift from mechanical to electronic systems. This electronic tuner has, for example, a PLL frequency synthesizer as the local oscillator, and in this system, stations can be easily stored by storing frequency division ratio data in memory. In addition, since these tuners are easy to control, they have additional functions such as automatically searching within the reception band and finding receivable stations by applying a microprocessor. There are many. Also,
In-vehicle radio receivers have also been proposed that automatically switch to another memory station when the receiver is out of the service area, thereby achieving automatic reception of the optimal station.

An object of the present invention is to provide an in-vehicle radio receiver that does not need to be stored in memory in advance, in order to further simplify such automatic reception.

Hereinafter, the present invention will be explained in detail with reference to the drawings.
FIG. 1 is a block diagram showing an embodiment of a vehicle-mounted radio receiver that tracks the same broadcast content station according to the present invention. Antenna 1 is connected to tuner 2, and a received signal is supplied to tuner 2. A part of the signal tuned by the tuner 2 is given to the level determination circuit 3. This level determination circuit 3 detects the reception level of the reception signal of the broadcast station tuned by the tuner 2 at a plurality of predetermined levels, and supplies this level to the control section 5. Further, a part of the demodulated output of tuner 2 is given to demodulation level detection circuit 4 . The demodulation level detection circuit 4 detects a pause in the demodulated audio, for example, if the broadcast content is speech, the pause period, and supplies this period detection signal to the control unit 5. Also, Chuyuna 2
The output is applied to a low frequency amplifier 9 via a muting circuit 8, amplified, and applied to a speaker 10.

Now, the data of the station currently being received is stored in the current station data area 6a of the current data memory 6, and this data is stored in the tuning voltage generation circuit 7.
The tuner 2 is tuned based on the output of the tuning voltage generating circuit 7. This tuning voltage generation circuit 7 is configured by, for example, a PLL frequency synthesizer.

In operation, first, the tuning voltage generation circuit 7 generates a tuning voltage based on the frequency data of the current station data area 6a. Then, the tuner 2 tunes to the current station based on the tuning voltage given from the tuning voltage generating circuit 7 and receives the broadcast program.
The received signal of the current station received by the tuner 2 is given to a level determination circuit 3, and the demodulated output is given to a demodulated level detection circuit 4. The output of this level determination circuit 3 is accumulated and averaged by the control section 5, and is stored as the reception level of the current station. When the demodulation level detection circuit 4 detects this voice and pause for a certain period of time, for example, this period is from several milliseconds to several hundred milliseconds, it performs the following series of operations. First, the control unit 5 applies a muting signal to the muting circuit 8, and in order to prevent the generation of noise, the control unit 5 attenuates the audio level and interrupts the audio. Next, the frequency data stored in the current station data area 6a and the inspection station data area 6b of the current data memory 6 are exchanged, and the frequency data stored in the inspection station data area 6b is changed to The signal is applied to the tuner 2 via the circuit 7. Tuner 2 tunes to that frequency and receives the corresponding station. Then, the reception level of the inspection station received by the tuner 2 is given to the level determination circuit 3, and the level is determined. The level signal determined by the level determination circuit 3 is provided to the control section 5. If this level is equal to or higher than a predetermined level, the control unit 5 stores the frequency data and reception level data of this station in the data area 11a of the memory device 11, and also stores the current station data area 6a of the current data memory 6 again. Frequency data and inspection station data area 6 stored in
The frequency data stored in b is replaced. Then, the control unit 5 transmits the muting signal given to the muting circuit 8.
Turn OFF to cancel audio interruption. Next, the frequency data in the inspection station data area 6b is incremented (or decremented) by the minimum inter-station space. These operations are performed within several milliseconds to several + milliseconds, but since they occur at the moment when the audio is interrupted, they do not interfere with the broadcast reception of the current station.
Then, when there is a moment when the audio is interrupted again, a muting signal is given to the muting circuit 8 to interrupt the audio in the same manner as described above, and the station corresponding to the frequency data in the inspection station data area 6b is received. Determine the reception level. If this reception level does not reach a predetermined level, the current station is immediately returned and this station is not stored. Every time these operations are performed several times, the frequency data currently in the inspection station data area 6b of the data memory 6 is temporarily saved in the control unit 5, and the stations stored in the memory device 11 are transferred to the inspection station data area 6b. If there is a station whose reception level exceeds the reception level of the station currently being received, the broadcast content of this station is determined as follows. That is, at the same time as switching to this station and taking in the reception level from the reception level determination circuit 3 to the control section 5, the demodulation level detection circuit 4
We inspected the output of the station and determined that there was a slight time delay, but based on the expected value regarding audio interruptions described later, if the audio was interrupted in the same way as the current station, there was a possibility that the broadcast content was the same. The station remains in the inspection station data area 6b. Now, the next time there is an audio interruption, check this station again, and if the same audio interruption occurs several to ten times, it will be determined that the broadcast content is the same, and the current station will be changed to this station. Switch. In this way, when the reception level check for the frequency data in the memory device 11 is completed, the frequency data saved in the control section 5 is returned to the inspection station data area 6b again.
The search for newly received stations continues while changing the data sequentially. Now, when the data area of the memory device 11 becomes full in this way, the data areas 11a to 11h in the memory device 11 are filled up.
The lowest reception level of the station is compared with the reception data of the newly discovered station, and if the reception level of the newly discovered station is higher, the data is replaced with new data. As a result, only recently received signals with good reception levels remain in the memory device 11. When the current station becomes weak, stations with the same broadcast content are discovered in the memory device 11 using the method described above, and the stations are switched one after another. Therefore, without operating the channel selection,
It is possible to track the same broadcast content station one after another in good condition.

By the way, in this method, when moving into the service area of a new broadcasting station, the most important point is to quickly capture this broadcasting station in memory and not to interfere with the broadcast reception of the current station. be. Now, as a result of statistical measurements of audio interruptions in broadcasting, the following has been found. In other words, regarding the amount of time that audio continues to be interrupted after a certain period of audio interruption is detected, the longer the period of audio interruption that is detected first, the longer the expected value of the period of time that the audio will continue to be interrupted. It is. For example, to give an example of experimental values, when an audio interruption of 85〓 is detected, the time for which there is a 90% possibility that it will continue after that is approximately 10ms, and 200ms.
When the audio interruption was detected, it was approximately 35ms. Judgment of broadcast content is made based on such probabilistic facts, but even if the time when broadcast audio is output is equal to the time when it is not, it is possible to determine that audio interruptions occur at the same time n times. If consecutive detections are made, the probability that the broadcast contents are different is (1/2) ⁿ , which is less than 0.1% when n = 10. It has also been confirmed that even if the audio is interrupted at a point where 90% or more of the audio interruptions can be expected to continue, it will have little effect on broadcast reception and will not cause any problems as long as the interruptions are not frequent. In other words, if you check the inspection station only when it satisfies both the requirements of leaving a certain interval, for example, one second, and detecting audio interruptions for a certain period of time, you can check the current station's broadcast reception. This means that it is possible to check the level of other stations with almost no influence. In addition, as mentioned above, when a long interruption time is detected, the expected value of the continuing interruption time becomes longer, so if audio interruptions continue at a certain interval, inspection should be performed according to the interruption time. It is also possible to increase the number of stations.

Needless to say, it is very advantageous to quickly search all bands and capture new stations in this way.

According to the present invention as described above, it is possible to realize an in-vehicle radio receiver that, when a certain broadcasting station is selected, automatically selects a station with the same broadcast content and a good reception level and automatically switches to the station. In some cases, very effective means can be provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the in-vehicle radio receiver of the present invention. In the figure, 1 is an antenna, 2 is a tuner, and 3
4 is a level determination circuit, 4 is a demodulation level detection circuit, and 5 is a level determination circuit.
is the control section, 6 is the current data memory, 6a
is a current station data area, 6b is an inspection station data area, 7 is a tuning voltage generation circuit, 8 is a muting circuit, 9 is a low frequency amplifier, 10 is a speaker, 11 is a memory device, and 11a to 11h are data areas. .

Claims (1)

[Claims] 1 a tuner, a level determination circuit that determines the level of a signal received by this tuner, a demodulation level detection circuit that detects the demodulated output level of the received signal and determines audio interruptions, and stores a plurality of data of tuning frequencies of the tuner. A memory device and a tuning frequency of the tuner are changed every time the sound is stagnant for a predetermined time or more, data of frequencies of received signals of a predetermined level or higher in a predetermined band are sequentially stored in the memory device in advance, and the stored data is stored in the memory device in advance. The data of the station with the lowest reception level among the data of the received frequency is compared with the data of the station with the higher reception level among the newly received data of the station, and the data of the station with the higher reception level is stored. A radio receiver characterized in that it is equipped with a control unit that controls the operation of the radio receiver.