JPH053931B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a radio receiver having a same program identification function.

BACKGROUND ART A pair of tuners capable of automatic channel selection are provided, and when one tuner is in a receiving state, the other tuner searches for another station that is simultaneously broadcasting the same program as the broadcast program it is currently receiving. A radio that automatically switches to the receiving station of the other tuner that is broadcasting the same program when the reception condition of one tuner deteriorates, thereby selecting a station with better reception condition. There is a receiver. According to this radio receiver, even if the reception condition deteriorates due to, for example, changing the service area of the broadcasting station while the car is driving, it will automatically switch to a station with better reception condition. Since the driver does not have to bother with tuning operations, such a radio receiver is suitable for use in a vehicle.

Such a radio receiver must include an identification circuit that identifies, based on the demodulated outputs of the pair of tuners, that the broadcast programs of the reception stations of both tuners are the same. Conventionally, this identification circuit has a configuration that detects the frequency component of each tuner output and identifies the identity of the program based on both detected components. Since the identification is carried out using the same method, the reliability of the identification operation is lacking.

Summary of the invention The present invention has been made in view of the above points, and
It is an object of the present invention to provide a radio receiver having a same program identification function that can more reliably identify the sameness of broadcast programs.

A radio receiver having the same program identification function according to the present invention detects frequency components of each demodulated output of a pair of tuners using at least two types of filter circuits having different frequency bands, and converts the frequency components into binary signals. It is configured to detect the logical coincidence of the pair of binary signals and identify the identity of the broadcast programs based on the number of pulses of the AND output of the respective coincidence detection outputs.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. In the figure, an RF (high frequency) received signal from an antenna 1 is supplied via a distributor 2 to a pair of tuners, , 3, and 4. The pair of tuners 3, 4 includes front ends 30, 40, IF (intermediate frequency) amplifiers 31, 41, detectors 32, 42,
It is composed of PLL controllers 33, 43 and received field strength level detection circuits 34, 44, and has a well-known PLL synthesizer type electronic tuner configuration capable of automatic tuning operation. The demodulated outputs of these tuners 3 and 4 are supplied to a switching circuit 5, which selects one of them, amplifies it with a low frequency amplifier 6, and supplies it to a speaker 7.

Each demodulated output of the pair of tuners 3 and 4 is further supplied to two signal processing circuits 8 and 9. One signal processing circuit 8 includes a pair of BPFs (band pass filters) 80 and 81 in a predetermined frequency band that detect frequency components of each demodulated output of the pair of tuners 3 and 4.
and a pair of zero cross detectors 82 as a waveform processing circuit that encodes each output of these BPFs 80 and 81 and converts them into binary signals of "0" and "1".
83 and these zero cross detectors 82, 83
and a coincidence detection circuit 84 which outputs a detection pulse when the logic of each output pulse matches. Similarly, the other signal processing circuit 9 also has a pair of
It consists of BPFs 90 and 91, a pair of zero cross detectors 92 and 93, and a coincidence detection circuit 94, and the signal processing circuit 8 is configured such that the frequency band of the pair of BPFs 90 and 91 is different from that of the pair of BPFs 80 and 81. As the coincidence detection circuits 84 and 94, exclusive NOR circuits having a well-known configuration can be used.

Each detection pulse outputted from the two signal processing circuits 8 and 9 is supplied to a gate circuit 10 to perform an AND operation. A counter 11 which receives the output pulses of the gate circuit 10 as a count input counts the pulses, and when the number reaches a predetermined number, generates a determination pulse and supplies it to the determination circuit 12 .
The determination circuit 12 generates an identical determination signal in response to this determination pulse and supplies it to the system controller 13.

The system controller 13 includes a CPU (central processing unit) 130 that plays a central role in operation, and an external memory 13.
1. Clock pulse generator 132 and frequency divider circuit 1
33, each in a pair of tuners 3 and 4.
Control of PLL controllers 33 and 43, switching control of switching circuit 5, received electric field strength level detection circuit 3
It performs operations such as storing the station number of the same broadcasting program station in the memory 131 based on the detection outputs of 4 and 44 and the sameness determination signal from the determination circuit 12, and sending out clock pulses to the clock pulse control circuit 14.
The clock pulse control circuit 14 is connected to the gate circuit 1.
0, the number of sampling pulses and the number of match determination reference pulses for controlling the counter 11 and the determination circuit 12 are set.

Next, the operation of this configuration will be explained.

Assuming that the demodulation output of the tuner 3 is currently selected by the switching circuit 5, the tuner 4 is in the search mode, and the system controller 13 always selects each receiving station based on the output of the received field strength level detection circuits 34 and 44. A program identification judgment is performed to determine whether or not the broadcast programs of both tuners are the same based on the judgment output of the reception field strength level detection and judgment circuit 12. When the same judgment signal is output from the judgment circuit 12, the program identification of the station is performed. The station number is stored in the memory 131 and weighted according to the received field strength level.

Regarding the same identification of broadcast programs, two signal processing circuits 8 and 9 divide and detect the modulated wave component and encode it into a binary signal of "0" and "1", and a coincidence detection circuit 84 is used for each band. , 94, and their outputs are ANDed by the gate circuit 10, and
When the number of pulses output from the gate circuit 10 is a predetermined number in succession, the determination circuit 12 issues an identical determination signal to the system controller 13. In this way, by decomposing the demodulated output of the tuner into frequency components and determining the identity of programs based on the frequency components of the two waves, program identification can be performed more accurately.

That is, when the tuners 3 and 4 are receiving the same program, the demodulated outputs output from the detectors 32 and 42, that is, the audio signals that are the broadcast contents, are the same over the entire frequency band. Being the same over all frequency bands also means that one frequency band component is the same among all frequency bands, so conventionally, only one predetermined frequency band component of the demodulated output of tuners 3 and 4 is extracted. The comparison was made to identify the identity of the programs.
In the embodiment according to the present invention, in addition to this signal processing circuit 8, a signal processing circuit 9 is further provided, and in a frequency band component different from one predetermined frequency band component of the signal processing circuit 8, the signal processing circuit 8 performs the same processing as the signal processing circuit 8. Since the programs are identified as the same program only when the sameness is confirmed by both signal processing circuits 8 and 9, the same program is identified by comparing only one frequency band component. Identification of identity is more accurate than that of .

If the reception condition of the tuner that is currently receiving deteriorates,
The system controller 13 detects this based on the output of the received field strength level detection circuit 34, and drives the switching circuit 5 to switch to the demodulated output of the tuner. At that time, system controller 1
3, the PLL controller 43 reads out the station number with the highest level among the station numbers that have been determined to be the same program and are weighted according to the received field strength level and stored in the memory 131, and receives the station with that station number.
control. This allows stations broadcasting the same program to be received in the best reception condition. At this time, the tuner that was previously receiving is placed in a search mode, and the reception field strength level of each receiving station is detected and the program identification is determined in the same way as in the case of the tuner.

Figure 2 is a time chart showing the tuner switching operation when the same program is being broadcast on stations A, B, and C, and it can be seen that the tuner output with better reception is always selected. Recognize.

In the above embodiment, a case was explained in which two pairs of BPFs were provided for detecting the frequency components of the demodulated output of the tuner, but the present invention is not limited to this, and it is also possible to provide three or more. This makes it possible to further improve the accuracy of identifying the identity of programs.

Effects of the Invention As explained above, according to the present invention, the demodulated output of a pair of tuners is decomposed into frequency components and
Since the identity of the programs is identified based on the frequency component of the wave or higher, the identity of the programs can be identified more reliably.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention;
FIG. 2 is a time chart showing the switching operation of the tuner in FIG. 1. Explanation of symbols of main parts, 1... antenna, 3,
4... Tuner, 5... Switching circuit, 8, 9... Signal processing circuit, 10... Gate circuit, 12... Judgment circuit, 13... System controller.

Claims (1)

[Scope of Claims] 1. A pair of tuners capable of automatic channel selection operation, and an identification circuit that identifies whether the broadcast programs of reception stations of both tuners are the same based on each demodulated output of the pair of tuners. and when the identification circuit identifies that the same broadcast program exists in each receiving station of the pair of tuners, the tuner output of the pair of tuners having a better reception condition is selected. In the radio receiver, the identification circuit includes a pair of filter circuits in a predetermined frequency band that respectively detect frequency components of demodulated outputs of the pair of tuners, and encodes each output of the pair of filter circuits and encodes each output. at least two signal processing circuits each comprising a pair of waveform processing circuits that convert into a binary signal and a coincidence detection circuit that outputs a detection pulse when the logic of each output of the pair of waveform processing circuits matches; The frequency bands of the pair of filter circuits provided in each of the signal processing circuits are different for each signal processing circuit, and the identity of the broadcast program is determined based on the number of pulses of the AND output of each detection pulse of the signal processing circuit. A radio receiver having a same program identification function.