JPH104365A - Radio receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow the radio receiver to receive a desired digital audio broadcast(DAB) program in a short time. SOLUTION: In the case of desiring the reception of a desired digital audio broadcast(DAB) program, a control section 32 applies electronic tuning/seek control to a tuner 22a to obtain an FM station broadcasting the program and uses a frequency list included in RDS data (multiplexed data) multiplexed on an FM broadcast signal from the FM station to obtain DAB station frequencies making the same program broadcast. Then a tuner 22b is tuned to the DAB station frequency to receive the desired digital audio broadcast(DAB) program.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio receiver, and in particular, includes a plurality of data fields into which audio signal data of a predetermined program is inserted by frequency multiplexing, and program arrangement data indicating correspondence between programs and data fields. The present invention relates to a radio receiver that receives, demodulates, and outputs a predetermined broadcast signal among a frequency multiplex broadcast signal and an FM broadcast signal including an information field to be inserted.

[0002]

2. Description of the Related Art Digital audio is now widely recognized for its excellent characteristics and ease of use, and is rapidly becoming popular. Against this background, digitalization of audio broadcasting has become active and digital audio broadcasting DAB (Digital Audio Broadcasting) has been realized in Europe. Digital audio broadcasting DAB
Performs orthogonal modulation on a frequency multiplexed broadcast signal including a plurality of data fields in which audio signal data of a predetermined program is inserted by frequency multiplexing and an information field in which program sequence data indicating the correspondence between the program and the data field is inserted. Transmit from a broadcasting station, receive the frequency multiplex broadcast signal in a frequency multiplex broadcast receiver, demodulate the frequency multiplex signal inserted in the data field according to the program separately specified by the user, convert it to an audio signal Output.

FIG. 4 shows a mode II frame structure employed in a DAB system. One frame length is 24 ms.
And a 2-symbol synchronization section SYNC and a 3-symbol high-speed information channel section FIC (Fast Information Channel).
l) and a data field part DFL of 72 symbols. The synchronization unit SYNC includes a null symbol and a synchronization information symbol used for recognizing the start point of the frame. In the high-speed information channel section FIC, time /
Date data, program arrangement data, service (program) name (label), program identification code SId (Service Identi
fication Code) is inserted, and a CRC for error correction is added at the end. Data field part DF
L is divided into 72 data fields, a broadcast signal of a predetermined program is inserted into each data field by frequency division multiplexing, and six to eight programs can be transmitted simultaneously from one broadcasting station. I have. Which program corresponds to which data field is specified by the array data of the program included in the high-speed information channel unit FIC. FIG.
In the above, the frame structure of mode II for satellite broadcasting using the 1.5 GHz band was shown, but the frame structure of mode I using the frequency band of 50 MHz to 250 MHz has almost the same structure, and the length of one frame is 96 ms. I have.

FIG. 5 is a diagram showing the configuration of a DAB transmitter.
~ 1m is analog audio signal (audio signal of each program)
Is a data compression unit that performs high-efficiency encoding (data compression) on. As a high-efficiency encoding method, PASC (Precisi) which is a compression method of DCC (Digital Compact Cassette) is used.
on Adaptive Subband Coding) and MDCT (ModifiedDisc)
There is a compression method such as reet Cosine Transformation). 2
Reference numerals a to 2m denote transmission path coding units for adding an error / detection correction code, and reference numeral 3 denotes a multiplexing unit which outputs output data of each of the transmission path coding units 2a to 2m according to program sequence data. It is mapped to a field (symbol) and time-division multiplexed. 4 is interleaved / OFD
M modulation section, and the modulation is orthogonal frequency division multiplexing OFDM
(Orthogonal Frequency Division Mutiplex), and interleaving is performed by rearranging the order of multiplexed signals in a symbol according to a predetermined format. 5 quadrature modulator for orthogonal transformation interleaving / I output from OFDM modulator (In-phase), by multiplying the Q (Quadrature) 90 ⁰ phase-shifted signals, respectively reference carrier and reference carrier wave signal, the 6 A frequency converter 7 for converting a transmission carrier obtained by quadrature modulation into a high frequency in the 50 to 250 MHz band (in the case of mode I), and 7 is a transmission power amplifier.

FIG. 6 is a block diagram of a DAB receiver (frequency multiplex broadcast receiver). 11 denotes an antenna, 12 is a front-end, 13 quadrature demodulator for quadrature detection by multiplying each of the intermediate frequency signal to the reference carrier and reference carrier 90 ⁰ phase-shifted signal outputted from the front end, 14 is a quadrature demodulator An A / D converter for performing A / D conversion of a baseband frequency multiplexed signal output from the A / D converter at a predetermined sampling frequency;
Is an audio decoding unit for decoding high-efficiency code data into original PCM audio data, and 17 is a DA converter for converting PCM audio data into an analog audio signal.

The transmission line decoding circuit 15 includes an FFT differential demodulation unit 15a, a selective decoding unit 15b, a deinterleave unit 15
c, a control microcomputer 15d, and a synchronization processor 15e. The FFT differential demodulation unit 15a performs an FFT process on the digital data output from the AD converter 14, identifies a frequency included in the frequency multiplexed signal of each symbol, and demodulates interleaved transmission data based on the identified frequency. . Deinterleave 15c is FF
The interleave is decomposed from the output data of the T differential demodulation unit to return to the original data sequence, and the selective decoding unit 15b performs error detection and correction on the deinterleaved data and inputs the data to the control microcomputer 15d. The control microcomputer 15d detects the symbol position (data field) of the program specified by the user based on the program sequence data included in the high-speed information channel unit FIC, and notifies the selective decoding unit 15b.
The selective decoding unit 15b outputs decoded data of the notified symbol (data field) to the audio decoding unit 16. The audio decoding unit 16 converts the input decoded data (high-efficiency code data) into the original PCM audio data and outputs it. Further, the audio decoding unit 16 outputs a data string P related to the program contents included in the audio data.
An AD (Program associated data), for example, information such as the name of the artist, the title of the music, and the lyrics is sent to the control microcomputer 15d. The control microcomputer 15d displays the input information on the display unit of the operation unit via the user interface. Further, the control microcomputer 15d sends the label (program name) included in the high-speed information channel FIC to the operation unit as appropriate in response to a user's request, and displays it.

[0007] The synchronization processor 15e performs FFT processing of the synchronization symbol after detecting the null symbol, calculates the frequency offset of the input signal, and converts the AFC signal into a quadrature demodulator 13e.
To adjust the reference frequency. Synchronous processor 1
5e calculates the correlation (shift amount) between the FFT result of the synchronization symbol and the original synchronization symbol, and calculates the result as the inverse FF.
T processing and the impulse response CIR (channel Imp
ulse Response) is output. Front end 12 is CI
The reference clock generator of the receiver, that is, the oscillation frequency of the voltage controlled crystal oscillator is synchronized with the transmission frequency of the transmitter based on the R signal.

[0008]

In order for a user to receive a DAB broadcast with such a DAB receiver, a DAB band is selected by band switching. The DAB receiver seeks the DAB broadcast band by a user's operation, and stops seeking when a radio wave having a predetermined reception electric field strength or more is received,
Perform synchronization acquisition. As a result, if the received signal is not a DAB signal, the seek operation is restarted. If the received signal is a DAB signal, the high-speed information channel unit FI included in the DAB received signal is restarted.
A label (DAB station name, program name) is extracted from C and displayed on the display unit, and the sound of the program corresponding to the label is demodulated and output. By operating the program selection button, the user sequentially switches the label and the audio to select a desired program. By the way, the DAB receiver does not output sound until the received electric field strength is tuned to a DAB broadcast frequency higher than a set level by a seek operation. For this reason, there is a problem that it is necessary to wait a considerable time until the sound of the desired program is output. In particular, because there are currently only a few DAB stations,
It takes a considerable amount of time to seek the AB station, and there is a problem that no sound is output during this time. In addition, DAB which was sought
If the station is not broadcasting the desired program, it has to seek again, which is an increasingly time-consuming problem.
As described above, the object of the present invention is to provide a DAB for a desired program in a short time.
An object of the present invention is to provide a radio receiver capable of receiving a broadcast.

[0009]

According to the present invention, a plurality of data fields into which audio signal data of a predetermined program is inserted by frequency multiplexing, and program array data indicating correspondence between programs and data fields are provided. A radio receiver that receives, demodulates, and outputs a specified broadcast signal among a frequency multiplexed broadcast signal and an FM broadcast signal including an information field into which is inserted, receives a predetermined broadcast signal and converts it into an intermediate frequency signal Tuner section, FM broadcast demodulation section for demodulating and outputting an FM broadcast signal, FM multiplexed data demodulation section for separating and demodulating multiplexed data multiplexed and transmitted to the FM broadcast signal, data according to a designated program A frequency multiplex broadcast demodulator for demodulating and outputting the broadcast signal of the program from the frequency multiplex signal inserted in the field, and an output signal of the FM broadcast demodulator and frequency multiplex broadcasting. A selection unit for appropriately selecting and outputting an output signal of the demodulation unit, and selecting a frequency of a frequency multiplex broadcasting station broadcasting the same program as that of the currently receiving FM broadcast from multiplexed data multiplexed and transmitted to the FM broadcast signal. Control, the tuner section is tuned to the frequency of the frequency multiplex broadcasting station automatically or by user selection, and the control of controlling the frequency multiplex broadcasting demodulation section to demodulate and output the broadcast signal corresponding to the program is performed. This is achieved by a radio receiver with a control unit to perform.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

(A) Configuration FIG. 1 is a configuration diagram of a radio receiver according to the present invention.
21b is an antenna, 22a is a first tuner unit for receiving an FM broadcast signal from a predetermined FM station and converting it to an intermediate frequency signal, and 22b is receiving a frequency multiplex broadcast signal from a predetermined DAB station and converting it to an intermediate frequency signal. This is the second tuner section. Although not shown, the tuner units 22a and 22b each include a front end including a tuning unit, a high-frequency amplifier, and a frequency converter, and a PLL that outputs a frequency signal according to a channel selection frequency.
Circuit (local oscillation circuit).

An F 23 demodulates and outputs an FM broadcast signal.
M broadcast demodulation unit, 23a is an FM IF filter,
23b is an F for demodulating the audio signal from the intermediate frequency signal.
The M detection circuit 23c is an S-meter connected to the S-meter terminal of the IF filter and detecting the reception electric field strength of the FM broadcast signal being received. Numeral 24 denotes a DAB broadcast demodulator for demodulating a broadcast signal of the program from a frequency multiplexed signal inserted in a data field (symbol) corresponding to the designated program and outputting the demodulated signal. In the DAB broadcast demodulation unit 24, 24a is a DAB IF filter, and 24b is a DAB
A signal demodulator (see FIG. 6), 24c is a DA converter for converting PCM audio data to analog, and 24d is a D converter.
The S-meter is connected to the S-meter terminal of the IF filter 24a for AB and detects the reception electric field strength of the DAB broadcast signal being received. When a DAB station is selected and a frequency multiplex broadcast signal from the station is input, the DAB signal demodulation section 24 demodulates the DAB signal (see FIG. 4) and extracts the label of each program from the high-speed information channel FIC. Function to input to the operation unit, the predetermined program is operated by the user, or
When it is determined by the control of the present invention described later, it has a function of demodulating a frequency multiplexed signal of a data field (symbol) corresponding to the program and outputting PCM audio data.

Reference numeral 25 denotes an output signal of the FM broadcast demodulator 23 and D
A selection unit 26 for appropriately selecting and outputting an output signal of the AB broadcast demodulation unit 24, an operation unit 26 provided with various buttons and a display unit, for example, 26a is a band switching button, 26b is a DAB station selection / The program selection button 26c is a display unit. 27 is a low frequency amplifier, 28 is a speaker,
An RDS demodulation unit 31 demodulates multiplexed data (RDS data) multiplexed and transmitted to the FM broadcast. RD
In the S demodulation unit 31, reference numeral 31a denotes a 57 KHz band-pass filter (BPF) that passes a 57 KHz sub-carrier amplitude-modulated based on RDS data, and 31b denotes an RDS decoder / clock recovery circuit. 31c is a group synchronization / error detection / correction circuit for demodulating RDS data from a filter output and recovering a clock, and detects errors of RDS data demodulated by an RDS decoder / clock recovery circuit 38b for each group. Detection is performed while synchronizing, and the error is corrected. The RDS data includes other FM stations (F
M frequency), DAB station (DAB station frequency) frequency list, and program identification code PI (Program Identification Co.)
de) etc. are included.

A control unit 32 controls the entire radio receiver. The control unit 32 performs the electronic tuning / seek control of the first and second tuners 22a and 22b based on the channel selection operation, and includes in the RDS data when the reception of the DAB broadcast of the same program as the FM broadcast is instructed. Control for switching to reception of DAB broadcasting automatically or in accordance with a user instruction by obtaining a DAB station frequency from a frequency list to be executed.

(B) Operation (b-1) Normal Reception Operation When a predetermined FM band is selected by the operation unit 26, the control unit 32 operates the first tuner unit 22a by user operation.
Is electronically tuned / seek controlled to search for an FM station whose received electric field strength is equal to or higher than a set level, and tunes to the FM station frequency by using the first tuner section. Further, the control unit 32 notifies the selection unit 25 that the FM station has been selected. The first tuner 22a converts the sought FM broadcast signal into an intermediate frequency signal, the FM broadcast demodulator 23 demodulates the FM audio signal from the intermediate frequency signal, and the selector 25 selects the FM audio signal. Output. When RDS data is multiplexed on the FM broadcast signal, the RDS demodulator 31 demodulates the RDS data and inputs the demodulated RDS data to the controller 32. The control unit 32 performs channel selection control according to a user operation based on the RDS data.

On the other hand, when the DAB band is selected by the operation unit 26, the control unit 32 performs electronic tuning / seek control of the second tuner unit 22b, searches for a DAB station whose reception electric field strength is equal to or higher than a set level, and The tuner section is tuned to the DAB station frequency. Further, the control unit 32 notifies the selection unit 25 that the DAB station has been selected. The second tuner unit 22b receives the frequency-division multiplexed broadcast signal from the DAB station that has been sought and converts it into an intermediate frequency signal. The DAB signal demodulation unit 24b demodulates the DAB signal from the intermediate frequency signal input from the tuner, extracts a label included in the high-speed information channel unit FIC of the DAB signal, inputs the label to the operation unit 26, and displays it on the display unit. . Further, the data field position (symbol position) of the program corresponding to the label being displayed is obtained from the program arrangement data included in the high-speed information channel section FIC of the DAB signal, and the frequency multiplexed signal inserted at the symbol position is demodulated / The PCM data obtained by the deinterleaving / decoding is input to the DA converter 24c, the DA converter 24c converts the PCM data into an analog signal, and the selector 25 selects and outputs an audio signal output from the DA converter. . The user operates the program selection button to sequentially switch the label and the sound to select a desired program.

(B-2) DAB Broadcast Reception Operation According to the Present Invention The above is a DAB broadcast reception operation similar to the conventional one. However, this receiving operation requires a considerable amount of time before the sound is output. Therefore, in the present invention, DAB broadcasting can be received by another method in addition to the above-described receiving operation. FIG. 2 is a processing flow of the DAB broadcast reception control of the present invention. When the user wants to receive a DAB broadcast of a desired program, the user selects the FM band. Thereby, the control unit 32
Outputs a sound by seeking a predetermined FM station by the electronic tuning / seek control of the first tuner unit 22a. At this time, the RDS demodulation unit 31 demodulates the RDS data and inputs the data to the control unit 32 (Step 101). The user determines whether the user wants to listen to the FM broadcast (program) from the voice (step 102). If the user does not want to listen to the program (service), the user performs a seek operation (step 103).
The subsequent operation is repeated.

When an FM broadcast station broadcasting a desired program is found by the above operation, the user inputs the fact to the control section 32 by operating a predetermined button. Thereby, the control unit 32 obtains the frequency of the DAB station broadcasting the same program (the same program) and the program identification code (SId code) from the frequency list included in the RDS data (step 104). Next, the control unit 32 controls the second tuner unit 22b.
Is tuned to the frequency of the DAB station, synchronization is acquired by referring to the output of the S meter 24d, and it is checked whether the DAB broadcast can be received (step 105).

If DAB broadcast can be received, it is checked whether automatic switching has been set by a switch or the like (step 106). If automatic switching has been set, the control unit 32 inputs the SId code to the DAB signal demodulation unit 24b and notifies the selection unit 25 that the DAB station has been selected (step 107). DAB signal demodulation unit 24
b is DAB when SId code (selected program) is input
The data field position (symbol position) of the selected program is obtained based on the program arrangement data included in the high-speed information channel section FIC of the signal, and the frequency multiplexed signal inserted at the symbol position is obtained by demodulation / deinterleaving / decoding. The obtained PCM data is input to the DA converter 24c,
The DA converter 24c converts the PCM data into an analog signal, and the selector 25 selects and outputs the audio signal output from the DA converter (Step 108).

On the other hand, if the automatic switching is not set in step 106, the control section 32 displays that the same program can be received by DAB broadcasting (step 109). If the user instructs the switching while watching this display (step 110), the reception of the DAB broadcast becomes possible in steps 107 and 108 thereafter. However, when the user does not give the switching instruction, the reception of the FM broadcast is continued as it is (step 111). Step 105
If the received electric field strength is below the set level and the DAB broadcast cannot be received, the control unit 32 displays that the same program as the FM broadcast cannot be received in the DAB broadcast (step 112). Thereafter, at the discretion of the user (step 11
3) If the FM broadcast being received is to be listened to as it is, the procedure goes to step 111, and if the DAB broadcast of another program is to be received, the processing after step 103 is executed.

In the above manner, since there are a large number of FM stations, it is possible to search for an FM station broadcasting a desired program in a short time, and use the frequency list included in the RDS data to search for the same program. The DAB station frequency for broadcasting can be obtained, and the DAB broadcast of a desired program can be received using the DAB station frequency.

(C) Modifications In the above description, the case where the first tuner for FM and the second tuner for DAB are used has been described. However, as shown in FIG. It can also be configured to be shared by. Incidentally, in FIG.
Is a tuner, and the configuration other than the tuner is the same as that of FIG. As described above, the present invention has been described with reference to the embodiments. However, the present invention can be variously modified in accordance with the gist of the present invention described in the claims, and the present invention does not exclude these.

[0022]

As described above, according to the present invention, DAB of a desired program
To receive a broadcast, seek the FM station broadcasting the program, and broadcast the same program using the frequency list included in the RDS data transmitted multiplexed on the FM broadcast signal from the FM station. Since the DAB station frequency is obtained and the DAB station frequency is used to receive the DAB broadcast of the program, the DAB broadcast of the desired program can be received in a short time. Further, according to the present invention, after searching for a program to be listened to by FM, and searching for a DAB station which broadcasts the program based on RDS data, the DAB station which broadcasts the program to be heard in one shot is switched. Broadcast can be received. Until the DAB broadcast is received, the FM broadcast sound is output, so that there is no silence time. Even when switching from FM to DAB, both programs are the same, so that there is no uncomfortable feeling.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a radio receiver according to the present invention.

FIG. 2 is a processing flow of DAB broadcast reception control of the present invention.

FIG. 3 is a configuration diagram of a radio receiver according to a modification of the present invention.

FIG. 4 is a diagram illustrating the structure of a DAB signal frame.

FIG. 5 is a configuration diagram of a DAB transmitter.

FIG. 6 is a configuration diagram of a DAB receiver.

[Explanation of symbols]

 22a, 22b Tuner 23 FM broadcast demodulator 24 DAB broadcast demodulator 24b DAB signal demodulator 25 Selection unit 26 Operation unit 31 RDS demodulation unit 32 Control unit

Claims (1)

[Claims] 1. A frequency-division multiplex broadcast signal including a plurality of data fields into which audio signal data of a predetermined program is inserted by frequency multiplexing, and an information field into which program arrangement data indicating the correspondence between the program and the data field is inserted. A tuner unit for receiving, demodulating and outputting a designated broadcast signal among FM broadcast signals, a tuner unit for receiving a predetermined broadcast signal and converting it to an intermediate frequency signal, and an FM for demodulating and outputting an FM broadcast signal A broadcast demodulation unit, an FM multiplex data demodulation unit for separating and demodulating multiplexed data multiplexed and transmitted to an FM broadcast signal, a broadcast signal of the program from a frequency multiplex signal inserted in a data field corresponding to a designated program Frequency demodulation section for demodulating and outputting an output signal of an FM broadcast demodulation section and an output signal of a frequency multiplexing broadcast demodulation section as appropriate. The selector selects the frequency of the frequency multiplex broadcasting station broadcasting the same program as the currently receiving FM broadcast from the multiplexed data multiplexed with the FM broadcast signal and sends the tuner to the tuner automatically or by user selection. And a control unit for controlling the frequency multiplex broadcast demodulation unit to demodulate and output a broadcast signal corresponding to the program by tuning to the frequency of the frequency multiplex broadcast station. Receiving machine.