JPH04151910A - Fm multiplex broadcast receiver - Google Patents

Abstract

PURPOSE:To receive a same program at all times by a receiver of a moving car or the like by revising and updating a reception frequency of a storage means into a reception frequency based on substitute frequency information included in a reception signal when a reception level goes to a prescribed value or below. CONSTITUTION:A mobile body such as a vehicle goes from a reception area A to B of a broadcast station, a reception level of a signal meter signal 50 from a tuner 11 is gradually decreased. A controller 1 detects the decrease in the reception level to the prescribed level or below and reads a frequency corresponding to the substitute frequency information included in a demodulation signal from a multiplex signal demodulator 2 from a substitute frequency memory 3 and the frequency in a frequency preset memory 4 corresponding to an operation button 5 is rewritten and updated into the substitute frequency. Thus, a same program is continuously received in the succeeding reception area B and the same program is always received.

Description

[Detailed description of the invention] 〈Industry〉Second field of use〉 The present invention relates to an FM multiplex broadcast receiver.

<Prior Art> In an FM multiplex broadcast receiver, alternative frequency lists 1 to 1 are added to a multiplexed signal. An alternative frequency is another frequency that broadcasts the same program as the one you are currently receiving, and by using this information, you can continuously receive the same program while moving while changing frequencies. It looks like this.

Figure 4 is a conceptual diagram of this, and when moving from reception area 8 to reception area B, the frequency f that is broadcasting the same program.
If you switch from frequency 0 to frequency 11, you will always receive the same program (
g becomes possible.

<Problem to be solved by the invention> On the other hand, ordinary car radios are equipped with a storage means for storing reception frequencies corresponding to predetermined operation buttons, that is, a preset memory that allows tuning to a desired frequency with the button. As mentioned above, there is a problem that if the frequency changes due to a change in the reception area, the BriseF1 memory becomes useless.

The present invention solves the above-mentioned conventional problems and provides an FM multiplex broadcast receiver that can switch the reception frequency and simultaneously rewrite the contents of the preset memory from the frequency currently being received to the frequency of the destination broadcasting station. The purpose is to provide

<Means for Solving the Problems> In order to achieve the object stated in -, the FM multiplex broadcast receiver of the present invention includes a storage means for storing reception frequencies corresponding to predetermined operation buttons, and an alternative frequency included in the reception signal. means for detecting frequency information; determining means for determining whether or not the received level has fallen below a predetermined value; The basic features include means for changing the receiving frequency and means for rewriting the Mj record storage means based on the changed frequency.

Effect> When the determining means for determining whether the reception level has fallen below a predetermined value determines that the reception level has fallen below the predetermined value, the detection means detects the alternative frequency information included in the received signal based on the alternative frequency information from the means for detecting the alternative frequency information included in the received signal. to change the receiving frequency. At the same time, the storage means for storing the reception frequency corresponding to the predetermined operation button is rewritten based on the changed frequency.

<Example> An embodiment of the present invention will be described below based on the drawings.

In FIG. 1, an antenna 10 inputs radio waves and sends them to a tuner 11, which outputs an FM'6i modulation signal 55 to the MPXl-2 and the multiplex signal demodulator 2, and controls a signal meter signal 50. It is configured to output to device 1. MPX12 is configured to convert the FM demodulated signal 55 into a stereo audio signal, and send this output to an audio circuit (not shown) where it is converted into audio.

The multiplex signal demodulator 2 is configured to input the FM demodulated signal 55, extract the FM multiplex signal portion from it, and demodulate the FM multiplex signal (digital). Then, the alternative frequency list 51 is extracted and sent to the alternative frequency memory 3, and the alternative frequency list 51 is sent to the alternative frequency memory 3.
5]. The alternative frequency list 51 is a signal represented by 2 bytes per frequency.If Hz) is being received, the frequencies of NHK Urawa and NHK Chiba, which are broadcasting programs at this time, will be stored as alternative frequencies in the alternative frequency memory. 3 is stored. Further, the value of the number n of alternative frequencies is also stored at the same time.

Control device fff 1. is mainly composed of a microcomputer, and controls the entire FM multiplex broadcast receiver.

The control device 1 also has a function of inputting a signal meter signal 50 from the tuner 11 and determining whether the reception level thereof has fallen below a predetermined value. In addition, the frequency of the channel specified by the operation button 5 is read out from the frequency preset memory 4 and the tuned frequency signal 52 is sent to the tuner 11.
The tuner 11 is tuned to the frequency. Furthermore, the control device 1 receives the signal meter signal 5.
0, if it is determined that the reception level is below a predetermined value -4 to
tuner 1 to receive the frequency with the highest reception level.
Control 1. At the same time, the corresponding channels of the frequency preseller 1 to memory 4 are rewritten to the corresponding frequency.

Next, the operation will be explained based on FIG.

As shown in FIG. 4, when a mobile object X such as a vehicle is moving from reception area A of broadcasting station A to reception area B of broadcasting station B, the signal meter signal 50 increases as the mobile object X moves away from broadcasting station A. The reception level S gradually decreases. The control device it 1 checks whether the reception level S has become less than the predetermined value 4Fi (step 20), and when it has become less than the predetermined value, sets the counter i to 0 (step 21).
), the alternative frequency list 51 is read out from the alternative frequency memory 3, and the tuner 11 is tuned to the first alternative frequency (step 22). Then, read the signal meter signal 50 (step 23), add 1 to the counter (step 24), and compare i with the number n of frequencies listed in the alternative frequency list 51 (step 25).
), the operation of sequentially switching the frequency and reading the signal meter signal 50 is repeated until i=n. Then, the differential meter signal 50 is set to the maximum alternative frequency by the tuner ]-1
After tuning, the contents of frequency preseller 1 to memory 4 are rewritten to the frequency (step 26).

As a result, the frequencies stored in the frequency preset memory 4 will always be realistic frequencies that can be received, and the preset function will never become unusable.

<Effects of the Invention> As explained above, the FM multiplex broadcast receiver of the present invention includes a storage means for storing reception frequencies corresponding to predetermined operation buttons;
means for detecting alternative frequency information contained in the received signal;
determining means for determining whether the received level has fallen below a predetermined value; means for changing the receiving frequency based on the alternative frequency information when the determining means determines that the received level has fallen below the predetermined value; and layer-resistant memory. Since the apparatus is provided with a means for rewriting the means on the basis of the changed frequency, it is possible to automatically switch reception and also to make effective use of the precera 1 memory.

[Brief explanation of the drawing]

11th block diagram showing an embodiment of the present invention, 2nd
The figure is a flowchart diagram, Figure 3 is a structural diagram showing the contents of the preset memory, and Figure 4 is an explanatory diagram of FM multiplex II (broadcasting). 1: Control device, 2: Multiple signal demodulator, 3: Alternative frequency Memory, 4: Frequency preset memory, 5: Operation button, 10
: Antenna, 11: Tuner, Co-2: MPX, 50
:Shifnal meter signal, 51:Alternative frequency list, 52
: Tuned frequency signal, 55: FM demodulation signal. Patent applicant: Clarion Co., Ltd. Representative: Patent attorney Kiyoshi Takahashi

Claims (1)

[Scope of Claims] Storage means for storing reception frequencies corresponding to predetermined operation buttons; means for detecting alternative frequency information included in the reception signal; and determination means for determining whether the reception level has fallen below a predetermined value. , comprising: means for changing the receiving frequency based on the alternative frequency information when the determining means determines that the reception level has fallen below a predetermined value; and means for rewriting the storage means based on the changed frequency. An FM multiplex broadcast receiver characterized by: