JPH05206902A - FM multiplex broadcasting receiver - Google Patents

Abstract

(57) [Abstract] [Purpose] In an FM multiplex broadcasting receiver, it is possible to reduce fluctuations in the received electric field strength and enable reception with high sensitivity. In an FM multiplex broadcast receiving device, an error in a data header of a digital signal received and demodulated is detected, and two antenna outputs are switched and selected based on the error.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving apparatus for receiving an FM multiplex broadcast in which a voice and characters different from the main program are transmitted and multiplexed with the FM broadcast, and is particularly suitable for mounting on a vehicle. The present invention relates to an FM multiplex broadcast receiver.

[0002]

2. Description of the Related Art In FM multiplex broadcasting, a digital signal corresponding to a voice, a character or a program code different from the main program is multiplexed with the current FM broadcast and transmitted. There is a demand for a receiving apparatus capable of reducing fluctuations in electric field strength and receiving with high sensitivity, particularly an FM multiplex broadcasting receiving apparatus for vehicles, which can receive with high sensitivity.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned points, and FM multiplex capable of receiving with high sensitivity by reducing the fluctuation of the received electric field strength in FM multiplex broadcasting. It is an object to provide a broadcast receiving device.

[0004]

In order to achieve the above object, the present invention is configured as follows.

That is, the present invention is an FM multiplex broadcast receiving apparatus for receiving an FM multiplex broadcast in which a digital signal other than a main program such as voice and characters is multiplexed and transmitted to the FM broadcast, and two antennas are provided. And an antenna selection circuit for switching and selecting both antenna outputs according to a switching signal, and detecting an error in the data header of the digital signal detected and demodulated from the antenna output selected by the antenna selection circuit, Error detection circuit that outputs the switching signal when an error is detected.

[0006]

According to the above construction, an error in the data header of the received and demodulated digital signal is detected, and the two antenna outputs are switched and selected based on the detected error. Can be received with sensitivity.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention. In this embodiment, description will be made by applying it to a vehicle-mounted radio receiver capable of receiving FM multiplex broadcasting.

The radio receiver 1 of this embodiment has two antennas 2, 3, an antenna selection circuit 4 for switching and selecting the outputs of both antennas 2, 3 according to a switching signal, and the output of the antenna selection circuit 4. A tuner unit 5 provided, a decoder 6 for extracting and demodulating a multiplexed signal from an FM detection output from the tuner unit 5, and a predetermined signal processing such as descrambling and error correction for a digital signal from the decoder 6. The digital signal processing unit 7 for extracting the voice signal data or the character signal data, the microcomputer 8 for control, and the error in the data header of the digital signal from the decoder 6 are detected, and the above-specified errors are detected. And a data header error detection circuit 9 that outputs a switching signal to the antenna selection circuit 4.

The tuner section 5 includes a front end 10 for selectively amplifying the output of the antenna selection circuit 4 and converting it to an intermediate frequency, and a detection circuit 11 for FM detecting the intermediate frequency signal from the front end 10. .

In this embodiment, when the reception condition deteriorates,
Considering that the quality of the multiplexed digital signal also deteriorates, an error in the data header of the digital signal is detected, and when an error more than a predetermined amount is detected, the data header error detection circuit 9 outputs a switching signal. Then, in response to this switching signal, the antenna selection circuit 4 is configured to switch and select the antenna output, whereby the optimum reception state is achieved.

As shown in FIG. 2, the structure of one frame of digital data in FM multiplex broadcasting is composed of a data header and 272 bits (one packet) of data, and the data header is a framing frame delimiter. It consists of a code (FC) and a mode control code (MC) that defines the signal structure in the frame.

The data header error detection circuit 9 is so constructed as to output a switching signal when at least one of the framing code and the mode control code is detected with a predetermined error or more.

FIG. 3 is a block diagram of another embodiment of the present invention, in which parts corresponding to the above-mentioned embodiments are designated by the same reference numerals.

In this embodiment, a framing code (FC) error detection circuit 12 is provided in place of the data header error detection circuit 9, and the detection circuit 12 detects an error in the framing code forming the data header. When a predetermined error or more is detected, a switching signal is output to switch the antenna output by the antenna selection circuit 4.

The other structure is the same as that of the above-mentioned embodiment.

Although the above-described embodiment has been described with respect to the on-vehicle radio receiver, the present invention is not limited to the radio receiver, and for example, data such as a map transmitted by FM multiplex broadcasting is received. The present invention can be similarly applied to a vehicle-mounted receiver that displays as.

[0018]

As described above, according to the present invention, the error of the data header of the received and demodulated digital signal is detected, and when the error more than the predetermined value is detected, the selection of the two antenna outputs is switched. Since it is configured to perform, it is possible to reduce fluctuations in the received electric field intensity and receive with high sensitivity.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a structure of data.

FIG. 3 is a block diagram of another embodiment of the present invention.

[Explanation of symbols]

1,1 ₀ Radio receiver 2,3 Antenna 4 Antenna selection circuit 6 Data header error detection circuit 12 Framing code error detection circuit

Front page continuation (72) Inventor Masayuki Takada 1-10-11 Kinuta, Setagaya-ku, Tokyo Inside the Japan Broadcasting Corporation Broadcasting Technology Laboratory (72) Inventor Tomohiro Saito 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Society, Broadcast Technology Laboratory (72) Inventor Toru Kuroda 1-10-11 Kinuta, Setagaya-ku, Tokyo Broadcasting Technology Laboratory, Japan Broadcasting Corporation (72) Inventor Shigeki Moriyama 1-1-10 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Corporation Broadcasting Technology Research Institute (72) Inventor Masanori Saito 1-10-11 Kinuta, Setagaya-ku, Tokyo Inside Broadcasting Technology Research Institute Japan Broadcasting Association (72) Satoru Yamada 1-10-10 Kinuta, Setagaya-ku, Tokyo No. 11 Broadcasting Technology Laboratory, Japan Broadcasting Corporation (72) Inventor Tadashi Isobe 1-10-11 Kinuta, Setagaya-ku, Tokyo Inside Broadcasting Technology Laboratory, Japan Broadcasting Association

Claims (2)

[Claims] 1. An FM multiplex broadcast receiving apparatus for receiving an FM multiplex broadcast for multiplexing and transmitting a digital signal such as voice and characters different from the main program in the FM broadcast, comprising two antennas and a switching signal. An antenna selection circuit that switches and selects both antenna outputs according to the above, and an error in the data header of the digital signal detected and demodulated from the antenna output selected by this antenna selection circuit is detected, and an error greater than a predetermined error is detected. And an error detection circuit that outputs the switching signal when the FM multiplex broadcasting receiver is received. 2. The FM multiplex broadcast receiver according to claim 1, wherein the error detection circuit detects an error in a framing code of a data header, and when an error more than a predetermined value is detected. An FM multiplex broadcast receiving device that outputs the switching signal.