JPH04329019A - Receiver - Google Patents

Abstract

PURPOSE:To surely provide RDS information by checking a received RDS data and stopping scanning at a frequency when no error takes place. CONSTITUTION:This receiver is provided with synthesizer system reception circuits 1-9, a demodulation circuit 25 demodulating an RDS data from a received broadcast signal, a decoder circuit 26 implementing error correction with respect to an RDS data from the demodulation circuit 25, a display means 46 displaying the RDS data or a data based on the RDS data, and searching keys Ksu, Ksd. In this case, when the searching keys Ksu, Ksd are operated, the reception frequencies of the reception circuits 1-9 are revised at every prescribed frequency step to scan the broadcast frequency band and when a broadcast station having the RDS data is received, the error of the received RDS data is checked. Thus, when no error takes place in the received RDS data, the scanning is stopped at that frequency.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver that uses RDS data.

0002

2. Description of the Related Art Some FM broadcast stations in Europe add RDS data to original audio signals.

[0003] This RDS data is a collection of digital data regarding broadcast stations and programs, etc., and this RDS data includes: AF list... Frequency list of broadcast stations on the same network. PI code: Program identification code. country code,
Contains program code, etc. Contains data such as.

[0004] Then, this RDS data is encoded for error correction, and the encoded RDS data has a frequency of 57 kHz (which is three times the frequency of the stereo pilot signal, 19 kHz). The subcarrier signal is balanced modulated, the modulated signal is added to a monaural signal or a stereo composite signal, and frequency multiplexed, and this multiplexed signal is FM
transmitted by waves.

[0005] Therefore, by using the AF list or PI code of RDS data, it is possible to receive a specific broadcast station or a specific program. Note that hereinafter, a broadcasting station that also transmits RDS data will be referred to as an "RDS station."

[0006] Literature: “Nikkei Electronics” 1987
August 24th issue

[0007]

SUMMARY OF THE INVENTION The present invention aims to make it possible to intentionally tune only such RDS stations, and in particular to provide RDS information to listeners in a reliable manner.

[0008]

[Means for Solving the Problems] Therefore, in the present invention, if the reference numerals of each part correspond to the embodiments described later, there are synthesizer-type receiving circuits 1 to 9, and received signals of the receiving circuits 1 to 9. A demodulation circuit 25 that demodulates RDS data from a broadcast wave signal, a decoder circuit 26 that performs decoding processing such as error correction on the RDS data from this demodulation circuit 25, and a display that displays RDS data or data based on the RDS data. Means 46 and search key Ks
When the search keys Ksu and Ksd are operated, the reception frequencies of the reception circuits 1 to 9 are changed every predetermined frequency step to scan the broadcast frequency band, and the broadcast frequency band having RDS data is scanned. When a wave is received, the received RDS data is checked for errors, and if the result of this check is that there are no errors in the received RDS data, scanning is stopped at the frequency at that time.

[0009]

[Operation] When searching for an RDS station, the search is automatically stopped only when RDS data can be successfully received. Therefore, the RDS data or data based on the RDS data is reliably displayed.

0010

[Embodiment] In Fig. 1, the receiving circuit is constructed in a synthesizer type, 1 is an antenna, and 2 is an antenna tuning circuit of an electronic tuning type. A wave signal Sr is extracted.

This signal Sr is then supplied to the mixer circuit 4 through the high frequency amplifier 3, and is also supplied to the VCO
11, the frequency fo is, for example, fo = fr +10.7MHz (i)
The oscillation signal So is extracted, and this signal So is supplied to the mixer circuit 4 as a local oscillation signal, and the signal Sr is frequency-converted into an intermediate frequency signal Si (intermediate frequency is 10.7 MHz). This intermediate frequency signal Si is then supplied to the FM demodulation circuit 6 through the intermediate frequency amplifier 5, where an audio signal (monaural signal or stereo composite signal) Sa and a modulated signal Sm modulated by RDS data are extracted. The signal Sa passes through the low-pass filter 7 and the low-frequency amplifier 8 to the speaker 9.
is supplied to

[0012] At this time, the VCO 11
Together with 2 to 15, the PLL 10 is configured. That is, the signal So from the VCO 11 is transmitted to the variable frequency divider circuit 12.
This frequency-divided signal is supplied to the phase comparison circuit 13, and the oscillation signal S with a reference frequency of 100 kHz is supplied from the oscillation circuit 14.
p is taken out, this signal Sp is supplied to the comparison circuit 13, and the comparison output is supplied to the VCO 11 through the low-pass filter 15 as its control voltage. Further, the output voltage of the filter 15 is supplied to the tuning circuit 2 as a tuning voltage.

Therefore, in a steady state, the frequency divided signal from the frequency dividing circuit 12 and the oscillation signal Sp have the same frequency, so the frequency fo of the oscillation signal So at this time
is fo = 100 kHz×N ‥‥‥ (ii
). Also, at this time, equation (i) holds true.

Therefore, as shown in FIG. 4, the frequency division ratio N
If you change it by "1" between 982 and 1187, the local oscillation frequency fo will change from 98.2MHz to 1187MHz.
Since it changes between 8.7 MHz at intervals of 0.1 MHz, the receiving frequency fr is 87.5 MHz to 108 MHz.
The frequency band of 0 MHz is changed in frequency steps of 0.1 MHz and in accordance with the frequency division ratio N.

Furthermore, 30 indicates a microcomputer for system control, 31 its CPU, 32
3 is a ROM in which the processing routine 50 shown in FIGS. 2 and 3 is written; 33 is a RAM for a work area;
4 is a RAM for storing various data, 41 to 44;
are ports, these memories 32-34 and ports 41-
44 is connected to the CPU 31 via the system bus 36.

The port 41 is connected to the frequency divider circuit 12, and a program to be described later is executed to set the frequency division ratio N in the frequency divider circuit 12. Although not shown, the RAM 34 is backed up by a battery and is nonvolatile, so that it retains written data even when the power is turned off.

Furthermore, the FM demodulation output and a part of the intermediate frequency signal Si are supplied from the demodulation circuit 6 to the detection circuit 23, and if the receiving level of the broadcast wave signal Sr is equal to or higher than the specified value and the broadcast wave signal Sr is A tuning detection signal Sq is extracted which is "1" when the tuning is correct and "0" when it is not, and this signal Sq is sent to port 4.
2.

Furthermore, the signals Sa and Sm from the demodulation circuit 6
is supplied to the bandpass filter 24 to extract the signal Sm, this signal Sm is supplied to the demodulation circuit 25 to demodulate the RDS data Sd, and this RDS data Sd is
d is supplied to the decoder circuit 26 for error correction before being supplied to the port 42. At this time, a signal Se indicating the result of error correction of the RDS data Sd, that is, an error flag Se indicating the presence or absence of an error in the RDS data Sd outputted from the decoder circuit 26 is taken out from the decoder circuit 26, and this signal Se is also supplied to port 42.

Furthermore, the port 43 has an up key Ku.
, down key Kd, registration key Kr, up search key Ksu, and down search key Ksd, and to the port 44, channel selection keys K1 to K10 are connected.

In this case, keys Ku to K10 are all constituted by non-lock type push switches. When the up key Ku and down key Kd are pressed, the receiving frequency fr is set to 100 kHz.
It is for raising or lowering in units.

Further, the registration key Kr is used to register the frequency data of the broadcasting station currently being received, for example, the frequency division ratio N, to a predetermined address in the RAM 33, and the search keys Ksu and Ksd are used to register the RDS station. This is for searching in the rising or falling direction of frequency. Further, the channel selection keys K1 to K10 are used to select the broadcasting station (frequency fr) registered to that key when pressed.

Further, 45 is a display controller;
46 is a display device, and this display device 46 digitally displays the reception frequency and the like.

According to this configuration, the following processing is performed by the CPU 31 executing the routine 50 shown in FIGS. 2 and 3.

<Power on> When the power is turned on, the CP
The process of U31 starts from step 51 of the routine 50, and then in step 52, the data of the last channel, that is, the frequency division ratio N of the broadcast station that was being received when the power was turned off last time, is stored in the RAM 34 at a predetermined value. This frequency division ratio N is set in the frequency division circuit 12 in the next step 53.

[0025] Therefore, when the power is turned on, the broadcast station that was being received when the power was last turned off is received.

Then, in the next step 54, predetermined data is supplied to the display controller 45.
The display device 46 displays data regarding the broadcast station currently being received;
For example, the frequency is displayed, and the broadcasting station being received is R.
If it is a DS station, its RDS data (or data based on RDS data) is also displayed.

Subsequently, the processing of the CPU 31 is performed in step 54.
The process proceeds to step 61, and in this step 61,
It is checked whether there is an input from the keys Ku to K10, and if there is no key input, the process repeats step 61 and waits for a key input.

<<Key input, channel selection, registration>> At step 61, when waiting for key input, the keys Ku ~
If you press any key of K10, the process will proceed to step 6.
1 to step 62, and in this step 62, the key input in step 61 is the up search key K.
If it is not the up search key Ksu, the process proceeds from step 62 to step 63, and in step 63 it is checked whether the key input in step 61 is the down search key Ksd. If the key is not the down search key Ksd, the process proceeds to step 69.

In step 69, the processing for key inputs other than the search keys Ksu and Ksd is as follows.
This is done as follows.

<Tuning selection using the key Ku or the key Kd> When the key input in step 61 is the up key Ku or the down key Kd, the frequency dividing ratio N set in the frequency dividing circuit 12 from the port 41 is set to the current value. than"
1” larger or smaller. However, when the frequency division ratio N reaches its maximum value or minimum value, the next value is set to the minimum value or maximum value.

[0031] Therefore, by pressing the key Ku or Kd, it is possible to tune into a broadcast on any frequency. Note that after this channel selection, the frequency division ratio N is stored in RAM3.
The data is written to a predetermined address of 4 as last channel data.

<Registration> When an arbitrary broadcasting station is selected, in step 61, press any channel selection key Ki among the selection keys K1 to K10 while pressing the registration key Kr.
When you press (i is any one from 1 to 10), R
The frequency division ratio N of the currently selected broadcasting station is written into the address of the AM 34 corresponding to the pressed key Ki.

[0033] Therefore, by this key operation, any broadcast station can be registered to any key Ki of the channel selection keys K1 to K10.

<Tuning by the tuning keys K1 to K10> When a broadcasting station is registered in the tuning key Ki, when any tuning key Ki is pressed in step 61, the RAM
34, the frequency division ratio N of the broadcasting station written there is read out from the address corresponding to the pressed key Ki, and this frequency division ratio N is set in the frequency division circuit 12. After this channel selection, the frequency division ratio N is written to a predetermined address in the RAM 34 as data of the last channel.

Therefore, by operating this key, it is possible to select the broadcasting stations registered in the channel selection keys K1 to K10.

As described above, in step 69, channel selection is performed using the up key Ku, down key Kd, channel selection keys K1 to K10, or registration using the registration key Kr.

When the process of step 69 is completed, the process returns to step 61 and waits for a key input again.

<Search for RDS station> In step 61, when waiting for key input, the search key Ksu
Alternatively, if Ksd is pressed, the process proceeds from step 61 to step 62, but when the key input in step 61 is the search key Ksu, the process proceeds from step 62 to step 64, and in this step 64, D=1
After that, the process proceeds to step 66.

When the key input in step 61 is the search key Ksd, the process proceeds from step 61 through step 62 to step 63, but further proceeds from step 63 to step 65, and in step 65, the process proceeds to step 63. =-1, and the process then proceeds to step 66.

Then, in step 66, the frequency dividing ratio N of the frequency dividing circuit 12 is incremented or decremented by the value D. Note that at this time, when the frequency division ratio N reaches its maximum value or minimum value, the next value is set to the minimum value or maximum value.

[0041] Therefore, the search key Ksu or K
Pressing sd will first raise or lower the receive frequency by 100kHz.

Then, the process proceeds to step 71,
In this step 71, ■ tuning detection signal Sq
will be checked. In this case, the tuning detection signal Sq
By checking, you can find out whether you are tuned to a broadcast wave whose reception level is higher than the specified value.

[0043] As a result of the check in item (2), if the tuner is tuned to the broadcast wave, the process proceeds from step 71 to step 72.

[0044] In this step 72, ■
The presence or absence of RDS data Sd is checked. In this case, by checking the RDS data Sd, it can be known whether the broadcasting station transmitting the RDS data Sd is tuned.

[0045] As a result of checking this item (■), RD
If a broadcast station transmitting S data Sd is being received, the process proceeds from step 72 to step 73.

[0046] Then, in this step 73, ■
The error flag Se is checked. In this case, if the currently selected broadcasting station is experiencing reception interference such as RF intermodulation or multipath, or if its reception level is so low that it is not suitable for receiving RDS data, the RDS data Sd. An error may have occurred, and the error flag Se indicates this.

[0047] Therefore, as a result of the check in item (2), if the error flag Se indicates that no error has occurred, the RDS data Se is valid, and the currently selected broadcasting station is the RDS data set. is a station, and
It is deemed suitable for reception, and the process proceeds from step 73 to step 74.

In step 74, predetermined data is supplied to the display controller 45.
The display device 46 displays data regarding the broadcast station currently being received;
For example, the frequency is displayed, and the received RDS data Sd (or data based on the RDS data Sd) is also displayed.

Next, in step 75, the current frequency division ratio N is written to a predetermined address in the RAM 34 as data of the last channel, and then the process returns to step 61 to wait for key input again.

However, in step 71, as a result of checking item (2), if the reception level is not tuned to a broadcast wave higher than the specified value, the process proceeds from step 71 to step 76. Furthermore, in step 72, if the result of checking item (■) is that the received broadcasting station is not an RDS station, the process proceeds from step 72 to step 76. Furthermore, in step 73, even when the error flag Se indicates that an error has occurred as a result of checking the item (■), the process proceeds from step 73 to step 76.

Then, in step 76, the key K
It is checked whether there is a key input from u to K10. If there is no key input, the process returns from step 76 to step 66, and if there is, the process returns from step 76 to step 62.

Therefore, when keys Ku to K10 are not operated, steps 66, 71 to 73, and 76 are repeated to search for an RDS station, and when a valid RDS station is selected, the RDS station is selected. The situation will continue. Further, if keys Ku to K10 are operated during the search for an RDS station, the operation according to the operated key will be performed thereafter.

[0053]

Thus, according to the present invention, when the search key Ksu or Ksd is pressed, a search for an RDS station is performed, and when an RDS station is found, the search is automatically stopped at that RDS station and the RDS station is searched. The station is in reception status.

[0054] In this case, especially according to the present invention, error-free broadcasting of RDS data Sd can be performed using effective RD.
Since the station is regarded as the S station and the search is stopped, the RDS data Sd can be displayed reliably.

That is, when searching for an RDS station, it is possible to stop the search when the modulated signal Sm is detected, but in that case, when the quality of the RDS data Sd is poor due to reception interference such as multipath, A problem may occur in which RDS data is not displayed even though the search for an RDS station has stopped. However, according to the present invention, the search is stopped only when it is confirmed in step 73 that there is no error in the RDS data Sd.
Since reception from that RDS station is continued, RDS data can always be displayed when the search is stopped.

Furthermore, before confirming that there is no error in the RDS data Sd in step 73, step 7
In steps 1 and 72, the presence or absence of broadcasting and the presence of RDS data Sd are checked, and only when these checks pass, the RDS data Sd is checked for errors, making it possible to quickly find a valid RDS station. can.

[Brief explanation of drawings]

FIG. 1 is a system diagram of an example of the present invention.

FIG. 2 is a flowchart showing part of an example of processing contents of the present invention.

FIG. 3 is a flowchart showing part of an example of processing contents of the present invention.

FIG. 4 is a diagram for explaining reception frequencies.

[Explanation of symbols]

2 Antenna tuning circuit 4 Mixer circuit 6 FM demodulation circuit 9 Speaker 10 PLL 11 VCO 12 Variable frequency divider circuit 13 Phase comparison circuit 15 Oscillation circuit 23 Detection circuit 25 Demodulation circuit 26 Decoder circuit 30 Microcomputer 31 CPU 32 ROM 33, 34 RAM 41-44 Port 45 Display controller 46 Display device 50 Processing routine Ku ~ Ksd operation keys K1 ~ K10 Channel selection key

Claims (1)

[Claims] Claim 1: A synthesizer type reception circuit, a demodulation circuit that demodulates RDS data from a broadcast wave signal received by this reception circuit, and a decoder that performs decoding processing such as error correction on the RDS data from this demodulation circuit. It has a circuit, a display means for displaying the RDS data or data based on the RDS data, and a search key,
When this search key is operated, the receiving frequency of the receiving circuit is changed every predetermined frequency step to scan the broadcast frequency band, and when a broadcast wave having the above RDS data is received, the received RDS data is and, as a result of this check, if no error has occurred in the received RDS data, the receiver stops the scanning at the frequency at that time.