JPH1032510A - Fm multiplex broadcast receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always display a program under tuning by a present turner by receiving FM multiplex broadcast so as to modulate data, abolishing immediately preceding data corresponding to the change of multiplexed data to output new data so as to avoid coexistance of data. SOLUTION: A tuner 1 receives FM multiplexed broadcast through an antenna 8 and gives a main channel signal for stereo and a sub channel signal for stereo to a stereo demodulation part 2. The part 2 outputs a right channel sound signal and a left channel sound signal based on the signals and gives reach of them to amplifiers 3 and 4. On the other hand, a composite signal including multiplexed data is outputted from he tuner 1 to give a data demodulation part 7. In the part 7, a data receiving part 71 fetches data from the composite signal to give a program analyzing processing part 72, which analyzes the program to display the contents of the program on a display part 52.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an FM multiplex broadcast receiver, and more particularly to an FM multiplex broadcast receiver for receiving an FM multiplex broadcast in which character data, graphic data, and the like are multiplexed on an audio signal.

[0002]

2. Description of the Related Art FM multiplex broadcasting includes a stereo main channel signal which is a sum signal of a left signal and a right signal of stereo sound, a stereo sub channel signal which is a difference signal between a left signal and a right signal, and a text broadcast. Is multiplexed and transmitted. At the receiver, F
The M multiplex broadcast is received, the stereo main channel signal and the stereo sub-channel signal are applied to a stereo demodulation circuit, and the right and left audio signals are demodulated and output. On the other hand, the multiplexed data is output as a composite signal, applied to a data demodulation circuit, and character data is extracted and displayed on a display.

A car stereo mounted on a car has a built-in FM tuner, a stereo demodulation circuit, and an amplifier.
Some devices are provided with a terminal for outputting a composite signal.
In such a car stereo, a data demodulation circuit is externally connected, a composite signal from the FM tuner is input to the data demodulation circuit, a display is mounted near the dashboard, and the driver can see character information. Some systems have been made extensible.

[0004]

However, in the above system, when the driver operates the car stereo and selects a reception frequency, the data demodulation circuit cannot know that the reception frequency has been changed. However, the data demodulation circuit receives data of different broadcasting stations in a mixed manner, which causes a problem that programs of a plurality of broadcasting stations are mixed.

[0005] Therefore, a main object of the present invention is to provide an FM multiplex broadcast receiver capable of automatically rewriting the immediately preceding data in response to a change in demodulated data. .

[0006]

The invention according to claim 1 is
An FM multiplex broadcast receiver for receiving an FM multiplex broadcast in which data is multiplexed into an audio signal, the FM multiplex broadcast receiver receiving the FM multiplex broadcast,
A tuner for outputting data, demodulating means for demodulating data based on the output of the tuner, and control means for discarding immediately preceding data in response to a change in demodulated data and outputting new data It is composed.

In the invention according to claim 2, the multiplexed data includes a broadcast station identification code indicating that the data is the same broadcast program, and the control means determines that the broadcast station identification code included in the demodulated data has changed. Rewrite data according to.

According to the third aspect of the invention, the multiplexed data includes a program index, and the control means rewrites the data in response to a change in the program index included in the demodulated data.

In the invention according to claim 4, the multiplexed data includes an update flag indicating that the program has been updated, and rewrites the data in accordance with the update flag included in the demodulated data being updated. .

[0010]

FIG. 1 is a schematic block diagram showing an embodiment of the present invention. In FIG. 1, a tuner 1
Receives the FM multiplex broadcast via the antenna 8 and supplies the stereo main channel signal and the stereo sub-channel signal to the stereo demodulation unit 2. The stereo demodulation unit 2 outputs a right channel audio signal and a left channel audio signal based on those signals, and supplies them to the amplifiers 3 and 4, respectively. The amplifiers 3 and 4 amplify the respective audio signals and make the speakers 5 and 6
Give to. These configurations constitute an FM receiver built in a conventionally known car stereo.

On the other hand, a composite signal including the multiplexed data is output from the tuner 1 and supplied to the data demodulation unit 7. The data demodulation unit 7 can be externally attached later, and includes a data reception unit 71 and a program analysis processing unit 72.
And a display unit 73. The data receiving unit 71 extracts data from the composite signal and supplies it to the program analysis processing unit 72. The program analysis processing unit 72 analyzes the program and displays the contents of the program on the display unit 73.

Here, the data included in the composite signal will be described. The multiplexed data includes an alternative frequency list, an identification code, a program index, and a program index update flag. The alternative frequency list indicates a frequency list when the same broadcasting station broadcasts radio waves of different frequencies depending on the area. The tuner 1 receives a radio wave of a certain frequency of the broadcasting station, and when the electric field strength becomes weak, refers to the alternative frequency list and switches the reception frequency so as to tune to another frequency.

When the tuner 1 switches the receiving frequency based on the alternative frequency list, the identification code PI is used to confirm whether the broadcast program at the frequency before the transition and the broadcast program at the frequency after the transition are the same. This is because the same broadcasting station sometimes broadcasts different programs depending on the area. The program index is a set of program numbers for all programs selected by the broadcasting station, and is changed by program reorganization or the like. When the program index is changed, the update flag for the program index is also changed at the same time.

FIG. 2 is a flowchart for explaining the operation of one embodiment of the present invention. Next, a specific operation of FIG. 1 will be described with reference to FIG. As described above, the tuner 1 refers to the alternative frequency list and receives the broadcast wave of the optimum reception level. Then, the composite signal is provided to the data demodulation unit 7 and the data reception unit 71
Determines whether or not the identification code PI has been received, and upon reception, determines whether or not the identification code PI has changed. If the identification code PI does not change, the program returns to the initial state. If the identification code PI changes, it is determined that the broadcast station has changed, the program stored so far in the program analysis processing section 72 is deleted, and new data is stored. Is written and displayed on the display unit 73.

Some broadcasting stations do not transmit the identification code PI. In this case, it is determined that the identification code PI has been received, and it is determined whether the program index update flag matches. . If they match, it is determined whether there is a change in the contents of the program number.If there is no change, the program returns to the initial state.If there is a change, it is determined that the broadcast station has changed. Delete programs up to. Also,
Even if the update flags do not match, if the index content changes by a certain amount or more, it is similarly determined that the broadcast station has changed, and the existing program is deleted.

Therefore, according to the embodiment of the present invention, even if the radio wave of the broadcast station to be received is switched by the tuner 1, if any one of the identification code PI, the program index, and the program index update flag changes, it is not changed until then. New data can be output in place of the above data. Therefore, if there is a tuner capable of extracting a composite signal, the data demodulation unit 7 is connected to any tuner,
By receiving the M multiplex broadcast, a teletext can be displayed on the display unit 73. Note that graphic data may be included as text broadcasting.

[0017]

As described above, according to the present invention, the FM
Receives multiplex broadcasts and demodulates data, according to changes in the multiplexed data, discards the previous data and outputs new data. The currently selected program can be displayed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of the embodiment of the present invention;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 tuner 2 stereo demodulator 3, 4 amplifier 5, 6 speaker 7 data demodulator 8 antenna 71 data receiver 72 program analysis processor 73 display

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiro Sata 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Hironori Mitou 2-chome Keihanhondori, Moriguchi-shi, Osaka No. 5-5 Sanyo Electric Co., Ltd. (72) Yoshinori Tomita 2-5-5 Keihan Hondori, Moriguchi City, Osaka Prefecture Inside (5) Sanyo Electric Co., Ltd. (72) Hiroyuki Namizaki Keihan, Moriguchi City, Osaka Prefecture 2-5-5 Hondori Sanyo Electric Co., Ltd. (72) Kanji Nakano 2-5-5 Keihan Hondori, Moriguchi-shi, Osaka Sanyo Electric Software Co., Ltd. (72) Inventor Takeharu Matsuda Osaka 2-5-5 Keihanhondori, Moriguchi-shi, Sanyo Electric Software Co., Ltd. (72) Inventor Motoaki Ogawa 1-1-1, Sakata, Oizumi-cho, Euraku-gun, Gunma FMS I Oh Sendy Liang within Bahado

Claims (4)

[Claims] 1. An FM multiplex broadcast receiver for receiving an FM multiplex broadcast in which data is multiplexed on an audio signal, comprising: a tuner that receives the FM multiplex broadcast and outputs data; And a control unit for discarding the immediately preceding data and outputting new data in response to a change in the data demodulated by the data demodulation unit. 2. The multiplexed data includes a broadcast station identification code indicating that the data is the same broadcast program, and the control unit changes a broadcast station identification code included in the data demodulated by the data demodulation unit. 2. The method according to claim 1, wherein the data is rewritten in response to the request.
M multiplex broadcast receiver. 3. The multiplexed data includes a program index, and the control unit rewrites the data in response to a change in a program index included in the data demodulated by the data demodulation unit. The FM multiplex broadcast receiver according to claim 1, wherein 4. The multiplexed data includes an update flag indicating that a program has been updated, wherein the control means updates the update flag included in the data demodulated by the data demodulation means. 2. The FM multiplex broadcast receiver according to claim 1, wherein data is rewritten according to the operation.