JP3159218B2 - Receiving machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Some FM broadcasting stations in Europe add RDS data to an original audio signal.

[0003] The RDS data is a collection of digital data related to broadcast stations and programs. The RDS data includes an AF list ‥‥‥ a frequency list of broadcast stations on the same network. PI code @ program identification code. Country code,
It has a program code and the like. Such data is included.

Then, the RDS data is subjected to an encoding process for error correction, and the RDS data subjected to the encoding process has a frequency of 57 kHz (this is a value three times the frequency of the stereo pilot signal of 19 kHz). The subcarrier signal is balanced-modulated, and the modulated signal is added to a monaural signal or a stereo composite signal and frequency-multiplexed, and the multiplexed signal is transmitted by an FM wave.

[0005] Therefore, a specific broadcast station or a specific program can be received by using the AF list or the PI code of the RDS data. Hereinafter, a broadcasting station that also transmits RDS data is referred to as an “RDS station”.
Call.

Reference: "Nikkei Electronics" August 1987
March 24 issue

[0007]

SUMMARY OF THE INVENTION The present invention makes it possible to intentionally select only such RDS stations, and particularly to make it possible to select RDS stations reliably and quickly. Things.

[0008]

Therefore, according to the present invention, a receiving circuit of a synthesizer system and a receiving level of a broadcast wave signal received by the receiving circuit are not less than a specified value .
To detect if it is tuned to the broadcast wave signal
A tuning detecting circuit, a demodulation circuit for demodulating the RDS data from the received broadcast wave signal of the reception circuit, performs decoding processing such as error correction to RDS data from the demodulating circuit, which is the decoding RDS Day
A decoder circuit for outputting an error flag indicating the presence or absence of a data error, a display means for displaying data based on the RDS data, a search key, the tuning detection circuit, the decoder circuit, and the search key. A control circuit for performing a predetermined tuning process according to each output of the control circuit, the predetermined tuning process by the control circuit, when the search key is operated by the user, the receiving frequency of the receiving circuit performs scanning broadcast frequency band to change for each predetermined frequency step, during this scan, the same
The detection output of the tone detection circuit is higher than the specified value
When it is indicated that the broadcast wave signal is tuned to the broadcast wave signal, it is determined whether the broadcast wave signal at this time has the RDS data. As a result of this determination, the broadcast wave signal
When having data, said from the decoder circuit
The error flag is checked, and as a result of the check, when no error occurs in the RDS data, the scan is stopped at the frequency at that time, the reception of the broadcast wave signal is continued, and the RDS is displayed by the display means.
The data based on the data is displayed. If the result of the determination is that the broadcast wave signal does not have the RDS data, the scan is continued.
Even when an error occurs in the data, the receiver is configured to continue the scan.

[0009]

The search is automatically stopped only when the RDS data is successfully received during the search of the RDS station. Therefore, the RDS data or data based on the RDS data is reliably displayed.

[0010]

In FIG. 1, a receiving circuit is constructed in a synthesizer system, 1 is an antenna, 2 is an antenna tuning circuit of an electronic tuning system, and this tuning circuit 2 is used for FM broadcast of a target frequency fr. The wave signal Sr is extracted.

The signal Sr is supplied to the high-frequency amplifier 3
Through the VCO 1
An oscillation signal So having a frequency fo of, for example, fo = fr + 10.7 MHz / (i) is taken out from 1 and this signal So is supplied to the mixer circuit 4 as a local oscillation signal. The intermediate frequency is converted to 10.7 MHz). Then, the intermediate frequency signal Si is supplied to the FM demodulation circuit 6 through the intermediate frequency amplifier 5 and the audio signal (monaural signal or stereo composite signal) S
a and the modulated signal Sm modulated by the RDS data are taken out, and the signal Sa is supplied to the speaker 9 through the low-pass filter 7 and the low-frequency amplifier 8.

At this time, the VCO 11 is connected to the circuit 1
Together with 2 to 15, the PLL 10 is configured. That is, the signal So from the VCO 11, is supplied to the variable frequency divider 12 is divided to a frequency of 1 / N, with the frequency division signal of this is supplied to a phase comparator circuit 13, an oscillation circuit 14
, An oscillation signal Sp having a frequency of 100 kHz as a reference is taken out, and 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. The output voltage of the filter 15 is supplied to the tuning circuit 2 as a tuning voltage.

Therefore, in the steady state, the frequency of the frequency-divided signal from the frequency dividing circuit 12 is equal to the frequency of the oscillation signal Sp, and the frequency fo of the oscillation signal So at this time is fo = 100 kHz × N ‥‥ ‥ (ii). At this time, equation (i) holds.

Therefore, as shown in FIG.
Is changed in steps of "1" between 982 and 1187, and the local oscillation frequency fo is set to 0.9 when the local oscillation frequency is between 98.2 MHz and 118.7 MHz.
Since it changes at intervals of 1 MHz, the reception frequency fr is 87.5
The frequency band from MHz to 108.0 MHz changes in 0.1 MHz frequency steps and in accordance with the frequency division ratio N.

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

The port 41 is connected to the frequency dividing circuit 12, and a program described later is executed to set the frequency dividing ratio N in the frequency dividing circuit 12. Although not shown, the RAM 34 is backed up by a battery and is made non-volatile, and retains the written data even when the power is turned off.

Further, a part of the FM demodulated output and the intermediate frequency signal Si is supplied from the demodulation circuit 6 to the tuning detection circuit 23, and the reception level of the broadcast wave signal Sr is higher than a specified value and the broadcast wave signal Sr The tuning detection signal Sq which is "1" when the tuning is correctly performed and "0" otherwise is taken out, and this signal Sq is supplied to the port 42.

The signals Sa and Sm from the demodulation circuit 6 are supplied to a band-pass filter 24 to extract a signal Sm, and the signal Sm is supplied to a demodulation circuit 25 to generate an RDS signal.
The data Sd is demodulated, and the RDS data Sd is supplied to the decoder circuit 26 to perform error correction, and then supplied to the port 42. At this time, the decoder circuit 2
6 to the signal Se indicating the result of the error correction of the RDS data Sd.
That is, the RDS output from the decoder circuit 26
An error flag Se indicating whether there is an error in the data Sd is extracted, and this signal Se is also supplied to the port 42.

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

In this case, each of the keys Ku to K10 is constituted by a non-locking type push switch.
The up key Ku and the down key Kd when you press them, is for raising or lowering the reception frequency fr with 100 k Hz units.

A registration key Kr is used to register the frequency data of the broadcasting station currently being received, for example, the frequency division ratio N at a predetermined address of the RAM 33.
su and Ksd are used to search for an RDS station in a frequency increasing or decreasing direction. Further, when the tuning keys K1 to K10 are depressed, the broadcasting stations (frequency fr) registered in the keys are selected.

Reference numeral 45 denotes a display controller;
Reference numeral 46 denotes a display device, which digitally displays a reception frequency and the like.

According to such a configuration, the following processing is performed by the CPU 31 executing the routine 50 in FIGS.

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

Therefore, when the power is turned on, the broadcasting station that was 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 on the currently receiving broadcast station,
For example, the frequency is displayed, and furthermore, the broadcasting station that is receiving
If it is a DS station, its RDS data (or data based on the RDS data) is also displayed.

Subsequently, the processing of the CPU 31 is executed at step 54.
To step 61, and in this step 61,
It is checked whether or not there is an input from the keys Ku to K10.
And wait for key input.

<< Key input, channel selection, registration >> In step 61, when waiting for key input, keys Ku to K
When an arbitrary key out of 10 is pressed, the process proceeds from step 61 to step 62. In this step 62, it is checked whether or not the key input in step 61 is the up search key Ksu. If not, the process proceeds from step 62 to step 63.
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.

Then, in this step 69, processing for a key input other than the search keys Ksu and Ksd is performed as follows.

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

Therefore, by pressing the key Ku or Kd, it is possible to select a broadcast of an arbitrary frequency. After this channel selection, the frequency division ratio N is written to a predetermined address of the RAM 34 as data of the last channel.

<Registration> When an arbitrary broadcasting station is selected, in step 61, while holding down the registration key Kr, an arbitrary tuning key Ki (i is 1 to 10) of the tuning keys K1 to K10. When any one of them is pressed, the frequency division ratio N of the currently selected broadcasting station is written in the address of the RAM 34 corresponding to the pressed key Ki.

Therefore, by this key operation, an arbitrary broadcasting station can be changed to an arbitrary key Ki of the tuning keys K1 to K10.
You can register to.

<Tuning by Tuning Keys K1 to K10> When a broadcasting station is registered in the tuning key Ki, in step 61, when any tuning key Ki is pressed, the pressed key of the RAM 34 is pressed. From the address corresponding to Ki, the division ratio N of the broadcasting station written therein is read out, and this 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 of the RAM 34 as data of the last channel.

Therefore, the broadcasting station registered in the tuning keys K1 to K10 can be selected by the key operation.

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

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, if a search key Ksu or Ksd is pressed while waiting for a key input, the process proceeds from step 61 to step 62. In the case of the search key Ksu, the process proceeds from step 62 to step 64, where D = 1 is set in step 64, and then the process proceeds to step 66.

When the key input in step 61 is the search key Ksd, the process proceeds from step 61 to step 63 through step 62, but further proceeds from step 63 to step 65, and proceeds to step 65.
At 5, D = −1, and then the process proceeds to step 66.

In step 66, the frequency dividing ratio N of the frequency dividing circuit 12 is incremented or decremented by the value D. At this time, when the frequency division ratio N reaches the maximum value or the minimum value, the next value is set to the minimum value or the maximum value.

Therefore, the search key Ksu or Ksd
By pressing, the reception frequency is first raised or lowered by 100 kHz.

Then, the process proceeds to a step 71, wherein
In this step 71, the tuning detection signal Sq is checked. In this case, by checking the tuning detection signal Sq, it is possible to know whether or not the reception level is tuned to a broadcast wave of a specified value or more.

Then, as a result of the check in this section, when it is tuned to the broadcast wave, the processing proceeds from step 71 to step 72.

Then, in this step 72,
A check is made to see if the RDS data Sd is present. In this case, by checking the RDS data Sd, the RD
It is possible to know whether or not the broadcasting station transmitting the S data Sd is selected.

Then, as a result of the check in this section, RD
If the broadcast station transmitting the S data Sd is being received, the process proceeds from step 72 to step 73.

Then, in this step 73,
The error flag Se is checked. In this case, if a reception failure such as RF intermodulation or multipath has occurred in the currently selected broadcasting station, or if the reception level is too low to be suitable for receiving RDS data, R
There is a possibility that an error has occurred in the DS data Sd, and the error flag Se indicates this.

Therefore, as a result of the check in this section, when the error flag Se indicates that no error has occurred, the RDS data Sd is valid. Assuming that the station is a station and is suitable for reception, the process proceeds from step 73 to step 74.

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

Subsequently, at step 75, the current frequency division ratio N is written as a last channel data at a predetermined address of the RAM 34. Thereafter, the process returns to step 61 and waits for a key input again.

However, if it is determined in step 71 that the reception level is not tuned to the broadcast wave whose reception level is equal to or higher than the specified value, the process proceeds from step 71 to step 76. Also, in step 72, as a result of the item check, if the received broadcast station is not an RDS station, the process proceeds from step 72 to step 76. Further, in step 73, when the result of the item check indicates that the error flag Se indicates that an error has occurred, 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 proceeds from step 76 to step 6
Returning to step 6, from step 76 to step 6
Return to 2.

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

[0053]

As described above, according to the present invention, when the search key Ksu or Ksd is pressed, the search for the RDS station is performed. When the RDS station is found, the search is automatically stopped at the RDS station and the RDS station is stopped. The station is in the receiving state.

In this case, in particular, according to the present invention, the RDS data Sd includes an error-free broadcast in an 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 the modulated signal Sm is detected during the search for the RDS station, the search can be stopped. In this case, when the quality of the RDS data Sd is poor due to a reception failure such as multipath, There may be a problem that the RDS data is not displayed even though the search for the RDS station is 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 the reception at the DS station is continued, the RDS data can always be displayed when the search is stopped.

Further, 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 or absence of RDS data Sd are checked. Only when these checks pass, errors in the RDS data Sd are checked, so that a valid RDS station can be quickly found. it can.

[Brief description of the drawings]

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

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

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

FIG. 4 is a diagram for explaining a reception frequency.

[Explanation of symbols]

 Reference Signs List 2 antenna tuning circuit 4 mixer circuit 6 FM demodulation circuit 9 speaker 10 PLL 11 VCO 12 variable frequency divider 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 To 44 ports 45 display controller 46 display device 50 processing routine Ku to Ksd operation keys K1 to K10 tuning keys

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H03J 7/18 H04B 1/16

Claims (1)

(57) [Claims] 1. A receiving circuit of a synthesizer system , and detecting whether a receiving level of a broadcast wave signal received by the receiving circuit is equal to or higher than a specified value and tuned to the broadcast wave signal. a tuning detecting circuit, a demodulation circuit for demodulating the RDS data from the broadcast wave signal received in the receiving circuit, performs decoding processing such as error correction to RDS data from the demodulation circuit, of the decoding process
An error flag that indicates the presence or absence of an error in the
A decoder circuit for outputting; a display means for displaying data based on the RDS data; a search key; and a control circuit for executing a predetermined tuning process in accordance with each output of the tuning detection circuit, the decoder circuit, and the search key. The predetermined tuning process by the control circuit, when the search key is operated by a user, changes the reception frequency of the reception circuit for each predetermined frequency step, and scans the broadcast frequency band. During this scan, the detection output of the tuning detection circuit is received during this scan.
When the broadcast signal indicates that the broadcast signal is tuned to the broadcast wave signal having the specified value or more, the broadcast wave signal at this time is converted to the RDS signal.
If the broadcast wave signal has the RDS data as a result of the determination, the error signal from the decoder circuit is determined.
If the lag is checked and no error is found in the RDS data, the scan is stopped at the frequency at that time and the reception of the broadcast wave signal is continued, and the RDS data is displayed by the display means. If the broadcast wave signal does not have the RDS data as a result of the determination, the scan is continued. Even if the RDS data has an error as a result of the check, A receiver that is configured to continue scanning.