JPH08274591A - Car radio receiver that can be tuned to the regional channel - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a vehicle-mounted receiver capable of automatically tuning to a channel of a region when the vehicle moves to a region covered by a broadcasting station. SOLUTION: When one broadcasting station group including a main broadcasting station and its branch broadcasting stations is selected from the key matrix 10, an audio signal is provided through a channel corresponding to an optimum modulation frequency provided from a receiver controller 20. The main tuner 14 for receiving the audio broadcast, the search tuner 24 for receiving the audio broadcast through the channels of the broadcasting stations belonging to the selected broadcasting station group, the plural received audio broadcastings are searched, and the optimal audio broadcasting is selected , A receiver controller 20 for providing the main tuner 14 with a corresponding modulation frequency at an optimum modulation frequency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver mounted on a vehicle, and more particularly, when a vehicle moves to an area covered by another broadcasting station, it automatically tunes to a channel of the area to establish a national network. The present invention relates to an in-vehicle receiver which continuously receives radio broadcasts broadcast from a main broadcasting station provided through a plurality of different branch broadcasting stations.

[0002]

2. Description of the Related Art Generally, in radio transmission, an audio signal is a radio frequency signal (RF carrier).
signal). The reason why such modulation is necessary is that its frequency band is too low for effective transmission of signals at audio frequencies.
Also, different carrier frequencies are used for each radio broadcasting station, and a channel having a predetermined frequency bandwidth is assigned to each broadcasting station. This bandwidth is necessary for transmitting a modulated carrier signal with a predetermined carrier frequency. A channel number is usually assigned to the channel used for each broadcasting station.
In the receiver, by selecting the desired channel number, the RF tuner can be tuned to a predetermined frequency band and the desired radio broadcast program can be received through the channel of that frequency band.

When a main broadcasting station equipped with a nationwide network simultaneously broadcasts a radio program to each region of the country, this radio program is sent to a branch broadcasting station of the main broadcasting station located in each region, and then each It is propagated through the channel assigned to the branch broadcasting station. Since each branch broadcasting station is assigned a different channel, the radio program is propagated to different channels in each region.
In this way, a receiver that has moved from one region to another tunes to the channel assigned to the local station that is responsible for that particular region in order to receive the radio program broadcast from the main station. I have to do it again. Therefore, when the receiver is mounted on a moving vehicle, there is an inconvenience that the receiver must be manually operated to a channel in charge of the area each time the vehicle passes through the area.

[0004]

SUMMARY OF THE INVENTION Therefore, the main object of the present invention is to automatically tune to a channel of a local area when a vehicle moves to an area covered by a local broadcasting station.
It is an object of the present invention to provide an in-vehicle radio receiver capable of continuously receiving a program broadcast from a broadcasting station having a nationwide network through a plurality of different branch broadcasting stations without operating a channel.

[0005]

In order to achieve the above object, a vehicle-mounted radio receiver installed in a vehicle and capable of continuously receiving the same program by automatically tuning when moving to another area. A key input unit having a plurality of selection keys for selecting any one of a plurality of broadcasting station groups each including a main broadcasting station and its branch broadcasting stations; and each of the broadcasting station groups includes key input means. Storage means for storing one set of modulation frequencies corresponding to the broadcast station group for specifying one of the broadcast station groups, and the storage in accordance with a command signal representing the selected broadcast station group. Means for extracting any one of the one set of modulation frequencies corresponding to the selected broadcasting station group from the means, and an audio signal corresponding to each of the extracted modulation frequencies are repeatedly received in order. A search tuner, means for generating a DC voltage proportional to the peak value of each of the received audio signals, and the DC voltages are compared to each other to determine the highest DC level from the extracted set of modulation frequencies. It comprises means for selecting an optimum modulation frequency to be provided and means for receiving an audio signal corresponding to said optimum modulation frequency.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will now be described in more detail with reference to the drawings. A block diagram of a vehicle-mounted receiver 100 according to the present invention is shown in the drawings. Generally, each main broadcasting station equipped with a nationwide network transmits a radio program produced by itself through a channel of a certain frequency band allocated to the main broadcasting station, and one or each of which is assigned a service area. Propagate to the above broadcasting stations. The main broadcasting station broadcasts a radio program modulated by a predetermined modulation frequency or carrier frequency through the allocated channel, and each branch broadcasting station selects the radio program from the main broadcasting station and services through the allocated channel. Broadcast to the area.

The main tuner 14 tunes the desired audio signal on the channel to the antenna 12 by tuning to the optimum modulation frequency provided by the reception controller 20.
To receive through. The audio signal thus received is supplied to the intermediate frequency amplifier (IF amplifier) 16. In the intermediate frequency amplifier 16, the frequency of the audio signal is converted into an audio signal in the intermediate frequency band and then supplied to the audio detector 18. The audio detector 18, which may also include an automatic gain control circuit (AGC), provides 4.5M from the intermediate frequency band audio signal.
The Hz audio signal is detected and a DC voltage proportional to the peak value of the received audio signal is generated.

DC generated from audio detector 18
The voltage is the main tuner 1 depending on the change of the DC voltage.
4 is used as a gain control signal for changing the gain.
This DC voltage allows the audio detector 18 to keep the output level of its audio signal constant. The detected 4.5 MHz audio signal is amplified by the audio amplifier 32 and output as an amplified audio signal necessary for driving the speaker 34.

The key matrix 10 incorporated in the receiver 100 has a plurality of keys used to select one of a plurality of station groups consisting of a main broadcasting station and a branch broadcasting station. According to the present invention, each key is assigned not a channel number but a service name for selecting a broadcasting station group including a main broadcasting station and its associated branch broadcasting stations. Therefore, by selecting the service name from the key matrix 10, it is not necessary to change to a new channel number each time the vehicle moves from one area to another. When a broadcasting station group is selected by pressing a key selected from the key matrix 10, a command signal indicating that the broadcasting station group has been selected is supplied to the receiver controller 20.

A data memory 30, which may consist of a look-up table, is used to store tuning information for multiple broadcaster groups. This tuning information is
Each includes a modulation frequency that selects a station group included in the station group corresponding to the group of modulation frequencies.

The receiver controller 20, which is also composed of a microprocessor, responds to the command signal from the key matrix 10 with the one corresponding to the selected broadcasting station group.
The modulation frequency of the group is retrieved from the data memory 30. The group of modulation frequencies searched in this way are supplied to the search tuner 24 in sequence and repeatedly.

A search tuner 24 connected to the antenna 22 sequentially and repeatedly searches channels of all broadcasting stations and branch broadcasting stations in the selected broadcasting station group corresponding to the modulation frequency group from the data memory 30. By doing so, it receives all programs broadcast from it. The audio signals received by the search tuner 24 are in turn provided to the intermediate frequency amplifier 26.

The intermediate frequency amplifier 26 converts the frequency signal of each audio signal into an intermediate frequency band and then supplies it to the audio detector 28. Audio detector 28
Generates a DC voltage proportional to the peak value of each audio signal from the intermediate frequency amplifier 26. This DC voltage is provided to the receiver controller 20.

At the receiver controller 20, the DC signals are compared to each other and the modulation frequency that yields the highest voltage level is selected. The modulation frequency thus selected is applied to the main tuner 14 as an optimum modulation frequency for receiving a required audio signal.

While particular embodiments of the present invention have been described above, it will be apparent to those skilled in the art that various modifications can be made without departing from the scope of the claims set forth herein.

[0016]

Even if the on-vehicle receiver according to the present invention which receives a desired radio broadcast through the currently tuned channel moves from one area to another, the receiver can be used in the area where the vehicle has moved. It is possible to receive a desired broadcast that is broadcast through a local channel.

[Brief description of drawings]

FIG. 1 is a block diagram of a vehicle-mounted radio receiver according to the present invention.

[Explanation of symbols]

 10 Key Matrix 12 Antenna 14 Main Tuner 16 Intermediate Frequency Amplifier 18 Audio Detector 20 Receiver Controller 22 Antenna 24 Search Tuner 26 Intermediate Frequency Amplifier 28 Audio Detector 30 Data Memory 32 Audio Amplifier 34 Speaker 100 Receiver

Claims (2)

[Claims] 1. A vehicle-mounted radio receiver, which is installed in a vehicle and can automatically synchronize and continuously receive the same program when moving to another area, each of which is a main broadcasting station and its branch broadcasting station. A key input unit having a plurality of selection keys for selecting any one of a plurality of broadcasting station groups including a plurality of broadcasting station groups, and for specifying one of the broadcasting stations included in each of the broadcasting station groups. Storing means for storing a set of modulation frequencies corresponding to the broadcasting station group; and the storage means corresponding to the broadcasting station group selected from the storage means in response to a command signal representing the selected broadcasting station group. A means for extracting any one of a set of modulation frequencies; a search tuner for sequentially and repeatedly receiving an audio signal corresponding to each of the extracted modulation frequencies; and a received audio signal. A means for generating a DC voltage proportional to the peak value of each of the signals and comparing the DC voltages with each other to select an optimum modulation frequency that yields the highest DC level from the extracted set of modulation frequencies. A vehicle-mounted radio receiver comprising means and means for receiving an audio signal corresponding to the optimum modulation frequency. 2. The radio receiver according to claim 1, wherein the broadcasting station group is selected by a service name assigned to represent each network of the broadcasting station group.