JPH06232778A - Rds receiver - Google Patents

Abstract

PURPOSE:To immediately utilize RDS data when an FM receiver is set again to an operating state from an inoperating state. CONSTITUTION:The receiver is provided with an FM tuner 2 selecting an FM broadcast, an MPX demodulation circuit 4 demodulating a voice signal, and an RDS demodulation circuit 6 demodulating an RDS signal. When an operation device 10 selects a channel selection frequency, power is supplied to the FM tuner 2, the RDS demodulation circuit 6, and an RDS synchronization error detection correction circuit 7 even at power interruption and RDS data multiplexed on an audio program are always stored in a storage device 9 via a controller 8. Thus, when power is applied to the receiver, newest RDS data are immediately obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an RDS receiver for receiving various service data which are multiplexed and broadcast in FM broadcasting or the like.

[0002]

2. Description of the Related Art There is FM multiplex broadcasting in which another subcarrier (57 KHz) is provided in addition to the main channel and subchannel of FM broadcasting, and channel selection information and information regarding program contents are multiplexed and provided. RD services such as multiplex broadcasting
It is called S (Radio Data System).

FIG. 3 is an explanatory diagram showing a transmission format of RDS data. As shown in FIG. 3A, RDS data is transmitted seamlessly in units of groups, and one group consists of 4 blocks. 1 as shown in FIG.
The block is composed of an information word area and a check word area including an offset word, and has a bit width of 26 bits. Also, as shown in FIG. 3C, information words (m ₀ , m ₁ ,
... m ₁₅ ) has a 16-bit width and serves as a signal indicating various characters and control codes.

On the other hand, the check words (c ₀ , c shown in FIG.
₁ , ... C ₉ ) has a 10-bit width, and is composed of an error correction code word of an information word and an offset word indicating a boundary between blocks and a start point of a group. As described above, the data length of one group of RDS is 104 bits, and the data is transmitted at a transmission rate of 1187.5 bits per second.

Now, in the information group of RDS, 0 to 1
There are 16 types of group types of 5, and each group type is classified into two types of versions A and B. For example, the group type “0A” is used for transmitting a frequency list (called AF) of the same net station and a program service name (called PS). Such RDS data is broadcast by being multiplexed with an audio broadcast program, and a plurality of group types are mixed and transmitted at a fixed ratio.

A group type "0A" PS transmits two characters per group. For example, in order to obtain a PS of all eight characters, four groups of group type "0A" signals must be received. In addition, AF outputs a frequency code converted to a specific code, but the group type "0
In "A", only two frequency data can be transmitted per group. Therefore, in order to reproduce the frequency list of the network station on the receiving side, it is necessary to receive a lot of RDS data. For example, the frequency list of a network station is 2
When it is composed of 5 types of frequencies, it is necessary to receive the group type “0A” of 13 groups in order to obtain this data. Assuming that the transmission rate of the group type “0A” is 40%, it takes 13 × 10 4 ÷ 1187.5 ÷ 0.4 = 2.85 seconds to receive these frequency data. Group types "2A" and "2
In order to obtain the radio text sent in "B", it is necessary to receive more groups, and the reception time will be longer accordingly.

[0007]

In order to receive RDS data using an FM receiver having an RDS receiving function, it is necessary to detect the offset word contained in each block and synchronize the RDS demodulation circuit. Therefore, it takes a considerable time for the RDS demodulation circuit to enter the synchronization state before receiving these RDS broadcasts after turning on the power switch of the FM receiver. Therefore, there is a drawback that the waiting time from turning on the power of the RDS receiver to receiving the desired RDS data becomes long.

The present invention has been made in view of the above conventional problems, and it is possible to immediately obtain RDS data after turning on the power switch of the FM receiver.
The purpose is to provide an S receiver.

[0009]

The invention according to claim 1 of the present application is an RDS receiver for receiving various kinds of data which are multiplexed and broadcast in a general broadcast, and a tuner for selecting a broadcast of a specific frequency, An audio signal demodulation unit that demodulates an audio signal from the output of the tuner, an RDS demodulation unit that demodulates RDS data that is multiplexed with the audio signal and broadcast from the output of the tuner,
A storage device for storing output data of the RDS demodulation unit;
A control device for storing RDS data obtained from the S demodulation unit in a storage device, and externally supplying power when the power is on, and at least supplying power to the tuner, the RDS demodulation unit, the storage device and the control device when the power is off. And a power supply control circuit that operates.

In the invention of claim 2 of the present application, the storage device is
In addition to the RSD data, the frequency data of a plurality of preset receiving stations is held, and the control device sequentially and periodically switches the receiving stations preset in the storage means when the power is off. It is characterized by having.

[0011]

According to the present invention having the above characteristics, the audio signal demodulation section demodulates the audio signal from the output of the tuner and the RDS demodulation section when receiving various data which are multiplexed and broadcast in general broadcasting. Is RD from tuner output
Demodulate S data. The power supply control device continues to supply power to the tuner, the RDS demodulation unit, the storage device, and the control device even when the power of the receiver is turned off, and stores the demodulated RDS data in the storage device. In this way, the RDS data is updated even when the power is off, so that the required RSD data can be obtained immediately.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An RDS receiver according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 shows the RD of the first embodiment.
It is a block diagram which shows the whole structure of an S receiver. In the figure, an antenna 1 is an antenna for receiving radio waves of FM broadcasting, and is connected to an FM tuner 2. The FM tuner 2 has an audio signal including a main channel and a sub channel, 57K.
It is a circuit for receiving the RDS signal multiplexed with the subcarrier of Hz, and its tuning frequency is controlled by the PLL circuit 3. The PLL circuit 3 is a circuit that stably holds the reception frequency of the FM tuner 2, and the selected frequency is input by the control device described later.

Next, the MPX demodulation circuit 4 is a circuit for demodulating the sum signal (L + R) and the difference signal (LR) of the stereo audio signal. The audio demodulation circuit 5 is a circuit for outputting the audio signal of the left (L) channel and the audio signal of the right (R) using a matrix circuit for the audio signal output from the MPX demodulation circuit 4. In this way, the MPX demodulation circuit 4 and the audio demodulation circuit 5 constitute an audio signal demodulation unit that demodulates an audio signal.

On the other hand, the RDS demodulation circuit 6 includes an FM tuner 2
It is a circuit for demodulating an RDS signal included in a 57 KHz subcarrier from an FM broadcast of a specific frequency output from. R
The DS synchronization error detection and correction circuit 7 inputs the data clock and the RDS bit signal output from the RDS demodulation circuit 6,
It is a circuit that divides a signal of each group into a plurality of blocks using an offset word, corrects a signal error using a check word, and reproduces an information word. The RDS demodulation circuit 6 and the RDS synchronization error detection / correction circuit 7 constitute an RDS demodulation unit for demodulating RDS data.

Next, the control device 8 is a circuit for controlling the overall function of the RDS receiver, which identifies the RDS data demodulated from the RDS synchronization error correction circuit 7 and stores the RDS data such as AF and PS in the storage device 9. It is a circuit to store. The storage device 9 is a memory that stores the RDS data output from the control device 8, and is configured by, for example, a RAM. still,
When the control device 8 is composed of a microcomputer, the storage device 9 is often included in the control device 8 itself.

The operating device 10 is an operating portion of the RDS receiver, and is used to turn on / off the power supply and select a receiving frequency, for example. The output of the control device 10 is given to the control device 8. The display device 11 is a part for displaying the contents operated by the operation device 10, and displays the power on / off, the reception frequency, and the RDS data.

The power supply control circuit 12 is a circuit that supplies various power supplies supplied from the power supply circuit 13 to a specific circuit of the RDS receiver by a control signal instructed by the control device 8. The power supply control circuit 12 keeps the FM tuner 2, the PLL circuit 3, the RDS even when the power switch of the operating device 10 is turned off.
Power is continuously supplied to the demodulation circuit 6, the RDS synchronization error detection / correction circuit 7, the control device 8, and the storage device 9, and the power is cut off to the other circuit units that reproduce the audio output. The control device 8 is also connected to the audio demodulation circuit 5, and the operating device 1
When the reproduction of the audio broadcast is instructed from 0, the audio demodulation circuit 5 is operated, and when the display of the RDS data is instructed, the data is output to the display device 11.

The RDS of the first embodiment configured as described above
The operation of the receiver will be described. First, in order to receive a normal audio program, the power switch of the operating device 10 is turned on and the reception frequency is selected. This reception frequency is output to the PLL circuit 3 via the control device 8. The PLL circuit 3 tunes the FM tuner 2 to a specific frequency. And M
The PX demodulation circuit 4 demodulates the audio signal, and the RDS demodulation circuit 6
Demodulates the RDS signal multiplexed on the carrier frequency of the broadcast program. If the program is a stereo broadcast, the audio demodulation circuit 5 outputs the audio signals of the L and R channels to an audio output circuit (not shown).

On the other hand, the output of the RDS demodulation circuit 6 is given to the RDS synchronization error detection / correction circuit 7, where any signal error is corrected and converted into RDS data in synchronization with the input clock. Then, this reproduction data is given to the control device 8,
The data content is identified, and the specific data is stored in the storage device 9.

Next, when the power switch of the operating device 10 is turned off, the power supply circuit 13 shuts off the power supply to the MPX demodulation circuit 4, the audio demodulation circuit 5, and the audio output circuit. However, the control device 8 continuously outputs the final tuning frequency instructed by the operating device 10 to the PLL circuit 3, and the FM tuner 2, the RDS demodulation circuit 6, the RDS synchronization error detection and correction circuit 7 via the power supply control circuit 12. , Holds the power supply of the storage device 9. For this reason, even if the RDS receiver is apparently inactive, the latest RDS data is input to the storage device 9, and the data is constantly updated if necessary.

Next, when the power of the RDS receiver is turned on again by the operating device 10 and the broadcast received until immediately before the power switch is turned off is received again, the RDS group and block have already been received. Since the synchronization is maintained, the above-described period for synchronization is not required, and the latest RDS data stored in the storage device 9 can be used, and various operations can be performed at the same time when the power switch is turned on. It is possible to provide RDS services.

An RDS receiver according to the second embodiment of the present invention will be described. FIG. 2 is a block diagram showing the configuration of the control device 20 used in the RDS receiver of the second example,
The other parts are the same as in the first embodiment. The present embodiment is a receiver having a function (hereinafter abbreviated as preset channel) capable of preliminarily storing and calling a plurality of broadcast frequencies such as broadcasts that users often listen to. Generally, the storage contents such as the reception frequency of the preset channel are stored in the storage device 9. Further, the control device 20 has a receiving station switching means 20a. The receiving station switching means 20a periodically switches the preset channels when the power is off.

When the RDS receiver is configured as described above, the preset RDS data of each station is periodically automatically received even when the power is off, and the desired RDS data is stored in the storage device 9. When the power switch is turned on as in the case of the first embodiment, the designated station is selected. Not only reception of audio broadcasting, various RDS data can be received immediately. Therefore, the user of the RDS receiver can use various RDS services at the same time as the tuning operation when the tuning operation by the preset channel is performed.

The third embodiment of the present invention is the RDS shown in FIG.
This is the case of a composite device in which the receiver is combined with a device having another audio output. A CD radio cassette tape player is one example, but other audio devices do not necessarily have to be integrated in the same housing as the RDS receiver. In this embodiment, an audio device such as a CD player or a cassette tape player is connected to the output end of the audio demodulation circuit 5, and the output of the audio demodulation circuit 5 is switched according to an instruction from the operation device 10. If the operation of the audio device is now selected, the RDS receiver is in a non-operation state, but the RDS data of the receiving station is stored in the storage device via the control device 8 or 20 as in the first and second embodiments. The data is stored in 9.

[0025]

As described in detail above, according to the present invention, the tuner and the RDS demodulator of the RDS receiver are always in operation. Therefore, when the power switch is turned on from the off state, various RDS data being broadcast can be immediately used without waiting time, which is an excellent effect.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of an RDS receiver according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing an overall configuration of an RDS receiver according to a second embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a signal format of RDS data.

[Explanation of symbols]

 1 Antenna 2 FM Tuner 3 PLL Circuit 4 MPX Demodulation Circuit 5 Audio Demodulation Circuit 6 RDS Demodulation Circuit 7 RDS Synchronization Error Detection and Correction Circuit 8, 20 Control Device 9 Storage Device 10 Operating Device 11 Display Device 12 Power Supply Control Circuit 13 Power Supply Circuit 20a Reception Station switching means

Claims (2)

[Claims] 1. An RDS receiver for receiving various kinds of data to be broadcast multiplexed with general broadcasting, the tuner selecting a broadcast of a specific frequency, and an audio signal demodulation for demodulating an audio signal from an output of the tuner. Section, an RDS demodulation section that demodulates RDS data that is multiplexed and broadcast to an audio signal from the output of the tuner, a storage device that stores output data of the RDS demodulation section, and RDS data that is obtained from the RDS demodulation section A controller for storing the data in the storage device, supplying power to the outside when the power is turned on, and at least the tuner and the RDS demodulator when the power is turned off,
An RDS receiver comprising: a power supply control circuit that supplies power to the storage device and the control device. 2. The storage device holds frequency data of a plurality of preset receiving stations in addition to RSD data, and the control device is preset in the storage means when power is turned off. 2. A receiving station switching means for switching the receiving stations sequentially and periodically.
The described RDS receiver.