JP2865017B2 - Radio receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio receiver used for a radio data system (RDS) put to practical use in Europe.

[0002]

2. Description of the Related Art RDS practically used in Europe
Is a system that multiplexes and transmits various data to FM broadcasts, and includes various types of data such as a broadcast station identification code (PI code) and an alternative frequency list (AF list) of the same network.

FIG. 3 shows a schematic configuration of an RDS radio receiver. In FIG. 3, reference numeral 1 denotes an antenna for receiving FM multiplex broadcast waves, and reference numeral 2 denotes a station selected to select a desired station and an intermediate frequency (I
F) a front end for converting to IF), 3 an IF amplifier for amplifying the IF signal, 4 a PLL synthesizer,
By changing the frequency division ratio data set in the program frequency divider in the PLL synthesizer 4, a desired station can be selected. Reference numeral 5 denotes an FM detection circuit.
The output of the M detection circuit 5 is supplied to an audio demodulation circuit 6 and separated into left and right stereo signals. Reference numeral 7 denotes a filter for extracting a sub-carrier of the radio data signal from the detection output of the FM detection circuit 5. You. Reference numeral 10 denotes a controller composed of a microcomputer or the like, and the RD generated by the decoder 9
The S data is stored in a memory in the controller 10 and used for various controls.

FIG. 4 shows alternative frequency list (AF list) data of the same network as the currently received broadcast stored in the memory in the controller 10. The controller 10 switches the tuning to an alternative frequency in a better reception state based on the alternative frequency. In the memory, the broadcast reception frequency f0 currently being received is also stored.
0, a currently received broadcast station identification code (PI code) and the like are stored.

The storage of the AF list in the above conventional example is performed as follows. First, the RDS data taken into the controller 10 is classified into information contents such as the PI code and the AF list after identifying a group type and a block type which are baseband structural elements. The AF list is transferred several times to transmit all the data. Each time one data is fetched, a numerical value corresponding to the frequency is written to the memory for the AF list.

[0006]

However, in the above-described conventional radio receiver, the AF list may not be completely captured. It typically requires one byte of memory to represent one frequency (eg, 87.9 → 04
hex), and the frequency range of the FM band in Europe is 87.5-108.0 MHz (2 kHz at 100 kHz).
This is because a memory of 1 byte × 206 = 206 bytes is required in order to be able to hold the AF list for all frequencies. Since such a large memory capacity is required, the number of AF lists to be normally stored is limited to 20 or the like. Therefore, when an AF list exceeding the memory capacity is transmitted, the AF operation is not performed. There was a problem of not being able to do it.

An object of the present invention is to solve such a conventional problem and to provide a radio receiver capable of efficiently storing an AF list frequency with a small memory capacity.

[0008]

According to the present invention, in order to achieve the above object, when storing an AF list frequency, the lowest frequency f0 is made to correspond to a predetermined address, and the received alternative frequency f is stored in a predetermined address. (F0-f) steps from (f0-f).

[0009]

Therefore, according to the present invention, the received AF list frequency is stored in association with the address, instead of being stored as a numerical value corresponding to the frequency as in the prior art.
It is possible to efficiently store all frequency steps with a small memory capacity.

[0010]

FIG. 1 shows a schematic configuration of a radio receiver according to an embodiment of the present invention, which differs from the conventional example shown in FIG. 3 only in the storage system in the controller. FIG.
, 11 is an antenna for receiving FM multiplex broadcast waves,
12 is a front end for selecting a desired station and converting it to an intermediate frequency (IF), and 13 is an I / A for amplifying an IF signal.
F amplifier 14 is a PLL synthesizer.
By changing the frequency division ratio data set in the program frequency divider in the L synthesizer 14, a desired station can be selected. Reference numeral 15 denotes an FM detection circuit. The output of the FM detection circuit 15 is supplied to an audio demodulation circuit 16 and separated into left and right stereo signals. 17 is an FM detection circuit 15
Is a filter for extracting a sub-carrier of a radio data signal from the detection output of the RDS signal. Reference numeral 20 denotes a controller composed of a microcomputer or the like. The RDS data generated by the decoder 19 is stored in a memory in the controller 20 and used for various controls.

The storage of the AF list in this embodiment is performed as follows. First, the RDS data taken into the controller 20 is classified into information contents such as a PI code and an AF list after identifying a group type and a block type which are baseband structural elements. The AF list is transferred several times to transmit all the data. When one data is fetched, the memory area of the address corresponding to the frequency is marked. That is, the bit in that area is set to 1.

For example, as shown in FIG.
Assuming that z corresponds to address 0 in the address of the frequency memory, when storing the AF list of the frequency fMHz, the number of steps from the lowest frequency (87.5 MHz) to that frequency, that is, (f−87) .5) ×
The bit of the 10th memory area is set to 1. f = 8
In the case of 8.3 MHz, (88.3-87.5) × 10 =
No. 8 Conversely, when searching for the frequency of the AF list being received, a location where the bit of the memory area is 1 is searched, and the number of steps corresponding to the address value is added to the lowest frequency (87.5 MHz). What is AF
It is a list.

[0013]

According to the present invention, as is apparent from the above embodiment, all of the alternative frequency lists (AF lists) can be stored with a smaller memory capacity than conventional ones, and the AF list cannot be stored. It can be prevented that the operation is not performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a radio receiver according to an embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a method of storing an AF list in a memory according to the embodiment.

FIG. 3 is a block diagram showing a schematic configuration of a radio receiver in a conventional example.

FIG. 4 is a schematic diagram showing a method of storing an AF list in a memory in a conventional example.

[Description of Signs] 11 Antenna 12 Front End 13 IF Amplifier 14 PLL Synthesizer 15 FM Detection Circuit 16 Audio Demodulation Circuit 17 Filter 18 RDS Signal Demodulation Circuit 19 Decoder 20 Controller

Claims (2)

(57) [Claims] When storing an AF list frequency, the lowest frequency f0 is made to correspond to a predetermined address, and the received alternative frequency f is stored as one bit in an address (f0-f) steps ahead of the predetermined address. Radio receiver with a controller that causes it to. 2. The radio receiver according to claim 1, wherein the controller comprises a microcomputer.