JPH04307806A - Receiver - Google Patents

Abstract

PURPOSE:To allow a receiver utilizing an RDS data to quickly and surely select a broadcast station with best listening sense by selecting a broadcast station with a frequency successful in a check based on prescribed priority according to a data based on an AF list. CONSTITUTION:An antenna tuning circuit 2 extracts an FM broadcast signal Sr whose object frequency is fr and a mixer circuit 4 receives a local transmitting signal So from a VCO 11 and converts into a intermediate frequency signal Si and an audio signal Sa and a modulated signal Sm modulated into an RDS data are extracted by an amplifier 5 and a demodulation circuit 6. The signal Sa is outputted to a speaker 9 via an LPF 7 and an amplifier 8. The signal Sm is given to a demodulation circuit 25 and a decoder circuit 26, from which a data Sd is inputted to a port 42. A CPU 31 sorts data representing coincident broadcast stations in the order of the reception of the broadcast wave when the PI code of the Sd is coincident with a PI code at reception. The broadcast station registered in keys K1-K10 by the operation of the channel selection keys K1-K10 are selected.

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 In FM broadcasting in Europe, RDS data is added to the original audio signal.

[0003] This RDS data is a collection of digital data regarding broadcasting stations, programs, etc., and this RDS data includes PI code...program identification code. country code,
Contains program code, etc. AF list: Frequency list of broadcast stations transmitting the same program. 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 PI code or AF list of RDS data, it is possible to receive a specific broadcast station or a specific program.

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

[0007]

SUMMARY OF THE INVENTION The present invention aims to improve the usability of a broadcast wave receiver having such RDS data. In other words, when a certain broadcast is selected using the AF list, but reception conditions are poor, the same program that is being broadcast on a different frequency can be reliably selected.

[0008]

[Means for Solving the Problems] Therefore, in the present invention, if the reference numerals of each part correspond to the embodiments described later, an AF list is extracted from RDS data, and broadcasting of frequencies shown in this AF list is performed. When a receiver that selects a station receives a broadcast on one frequency, it selects a broadcast station on the frequency in the AF list, checks whether the selected broadcast station is transmitting RDS data, and then As a result of the check, when RDS data is being transmitted, the PI code of this RDS data is checked, and as a result of this check, if the PI code matches the PI code at the time of receiving the broadcast on the first frequency, this PI code is The data indicating the broadcast station with the matching code and the reception level of the broadcast wave are stored, and this stored data is sorted in the order of reception level, and when a predetermined key operation is performed, the sorting is performed for each key operation. Data indicating the broadcasting stations are sequentially extracted from the results, and the channel selection is performed based on the extracted data.

[0009]

[Operation] Various checks are performed in a predetermined priority order according to data based on the AF list, and broadcast stations with frequencies that pass the checks are selected, and broadcasts are selected for each predetermined key operation. The station is changed to the next candidate, and the most suitable broadcasting station based on hearing is selected.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 indicates an antenna, and reference numeral 2 indicates an antenna tuning circuit using an electronic tuning method.The tuning circuit 2 extracts an FM broadcast wave signal Sr of a target frequency fr.

This signal Sr is then supplied to the mixer circuit 4 through the high frequency amplifier 3, and is also supplied to the VCO
From 11, the frequency fo is 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.
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.
It changes at intervals of 0.1 MHz between 0 MHz and in accordance with the frequency division ratio N.

Further, 30 indicates a microcomputer 30 for system control, 31 indicates its CPU,
32 is a ROM in which the processing routine 50 shown in FIGS. 2 and 3 is written, and 33 is a RAM for a work area.
, 34 is a RAM for storing various data, 41-
44 is a port, and these circuits 32 to 34 and 41 to 44 are connected to the CPU 31 through a 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.

Further, a part of the intermediate frequency signal Si is taken out from the mixer circuit 4, and this signal Si is supplied to the detection circuit 21 to generate an electric field whose DC level changes in accordance with the reception level of the broadcast wave signal Sr. The detection signal Ss is taken out, and this signal Ss is supplied to the A/D converter 22 where it is A/D converted into a digital signal and then supplied to the port 42.

Further, the FM demodulated output and a part of the intermediate frequency signal Si are supplied from the demodulation circuit 6 to the detection circuit 23, which becomes "1" when the broadcast wave signal Sr is being received, and "1" when the broadcast wave signal Sr is not being received. Detection signal Sq becomes 0”
is taken out, and this signal Sq is supplied to port 42.

Furthermore, the signals Sa and S from the demodulation circuit 6
m is supplied to the bandpass filter 24 and the signal Sm
is extracted, this signal Sm is supplied to the demodulation circuit 25 to demodulate the RDS data Sd, and this RDS data Sd is supplied to the decoder circuit 26 for error correction and then supplied to the port 42. Also, at this time,
A signal Se indicating the result of error correction of the RDS data Sd, that is, an error flag signal Se indicating the presence or absence of an error in the RDS data Sd output from the decoder circuit 26 is extracted 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, search key K
s and a change key Kc are connected to the port 44, and channel selection keys K1 to K10 are connected to the port 44.

In this case, the 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.

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, at a predetermined address in the RAM 33. Furthermore, the search key Ks is used to search for the same program as the program being received that is being broadcast on a different frequency, and the change key Kc is used to change the channel selection to the same program on that different frequency. It is for the purpose of In addition, the channel selection keys K1 to K
10 is used to select the broadcasting station (frequency fr) registered to that key when pressed.

Furthermore, 45 is a display controller, and 46 is a display device. As shown in FIG. 7, the display device 46 digitally displays, for example, the frequency indicated by the AF list in accordance with the user's key operations.

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.

[0026] Therefore, when the power is turned on, the broadcast station that was being received when the power was last turned off is received.

[0027] Subsequently, the processing of the CPU 31 is performed in step 52.
Proceeding to step 53, in this step 53,
A PI code is extracted from the RDS data Sd from the decoder circuit 26, this PI code is written to a predetermined address in the RAM 33, and then in step 54,
Waiting for key input.

<<Key input, channel selection, registration>> At step 54, when waiting for key input, the keys Ku ~
When you press any key from Kc, K1 to K10,
The process proceeds from step 54 to step 55. In step 55, it is checked whether the key input in step 54 is the search key Ks. If it is not the search key Ks, the process proceeds from step 55 to step 56. In this step 56, it is checked whether the key input in step 54 is the change key Kc, and if it is not the change key Kc, the process proceeds from step 56 to step 57.

In step 57, the search key Ks and change key Kc are used for channel selection, registration, etc.
Processing for key inputs other than the following is performed as follows.

<Tuning selection using key Ku or key Kd> When the key input in step 54 is the up key Ku or 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. Further, the PI code is also written into the RAM 33.

<Registration> When an arbitrary broadcasting station is selected, in step 54, while pressing any channel selection key Ki (i is any one of 1 to 10) among the selection keys K1 to K10, , when the registration key Kr is pressed, 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 selection using 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 54, 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. Further, the PI code is also written into the RAM 33.

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 57, 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 57 is completed, the process returns to step 54 and waits for a key input again.

<<Searching for AF Station>> When an arbitrary broadcasting station is selected and a key input is being waited for in step 54, when the search key Ks is pressed, the process returns to step 54.
The process proceeds to step 55, but in this case, the search key Ks
is pressed, the process further advances from step 55 to step 61, and in this step 61, the AF list is extracted from the RDS data Sd, and for example, as shown in FIG. 5A.
As shown in , N frequency data AFD(1) to AFD(N) in this AF list are written to the RAM 33.

Subsequently, in step 62, the software counter CT is set to "1", and then in step 63, the CT-th frequency of the AF list (FIG. 5A) formed in the RAM 33 in step 61 is set. The data AFD(CT) is extracted, and the broadcasting station of this frequency is selected. In this case, since CT=1, the broadcasting station with data AFD(1) of the first frequency in the AF list is selected.

[0040] Then, in step 71, ■
The tuning detection signal Sq and the presence or absence of the RDS data Sd are checked. In this case, the tuning detection signal Sq
By checking, you can know whether broadcast waves are being received, and by checking RDS data Sd, you can know whether you are tuning into a broadcasting station that is transmitting RDS data Sd. can.

[0041] As a result of checking this item (■), RD
When the broadcasting station transmitting S data Sd is received and tuned, the process proceeds from step 71 to step 72.
Proceed to.

[0042] In this step 72, ■
The error flag signal Se is checked. In this case, if reception interference such as RF intermodulation or multipath occurs with the currently selected broadcasting station, there is a possibility that an error has occurred in the RDS data Sd. That is,
RDS is a digital signal and also allows error correction.
If the reception condition is such that an error occurs in the data Sd, the quality of the demodulated audio signal Sa is poor,
It is considered unsuitable for reception.

Therefore, as a result of checking the item (■), if the error flag signal Se indicates that no error has occurred, the process proceeds from step 72 to step 73.
Proceed to.

[0044] Then, in this step 73, ■
A check of the PI code is performed. In other words, the PI code of the RDS data Sd of the broadcast currently being received is
P written to RAM33 in step 53 or 56
By checking whether the program matches the I code, it is checked whether the program of the broadcast station selected in step 72 is the same as the program of the broadcast station selected in step 52 or 56. If it's the same program,
Even if you switch broadcast stations, there will be no problem with the program content.

[0045] As a result of checking the item (■), if the programs are the same (if the PI codes match), the process proceeds from step 73 to step 74.

[0046] In this step 74, ■
The electric field detection signal SS is checked. In this case, the level of the detection signal Ss corresponds to the reception level of the broadcast wave currently being received.
Good N and C/N.

Therefore, it is checked whether the level of the detection signal Ss in the item (■) is above a predetermined value, and when it is above the predetermined value, the process proceeds from step 74 to step 75.
Proceed to.

In step 75, the frequency data AFD (CT) at this time and the level of the detection signal Ss in the section (2) are temporarily stored in the RAM 33.

Subsequently, in step 76, the counter CT is incremented by "1", and then in step 7
In step 7, it is checked whether the processing of steps 71 (and 72 to 75) has been executed for all the frequency data AFD(1) to AFD(N) broadcast stations in the AF list of the RAM 33, and it is determined whether the processing has been executed for all of them. If not, the process returns from step 77 to step 63.

Further, in step 71, when checking item (2), if the broadcasting station transmitting the RDS data Sd is not selected, the process skips steps 72 to 75 from step 71 to step 76. Proceed to. Similarly, in steps 72 to 74, when checking items ■ to ■, if the check results are negative,
The process skips subsequent steps from steps 72-74 and proceeds to step 76.

[0051] In this way, for all the frequency data AFD(1) to AFD(N) broadcasting stations in the AF list of the RAM 33, the check in section (■) is executed, and then the checks in sections (■) to (■) are executed. , These checks in items 1 to 2 are executed only when the previous check passes. Then, only the frequency data AFD (CT) and the level of its detection signal Ss that have passed all the checks in items ① to ② are sequentially stored in the RAM 33. Furthermore, Figure 5
B is AF list frequency data AFD(1) to AF
A case is shown in which four of the D(N) broadcasts pass the checks in items 1 to 2 and their data remains in the RAM 33.

[0052] When the check is completed for all the frequency data AFD(1) to AFD(N) in the AF list, the process proceeds from step 77 to step 78, and in step 78, the RAM is
The frequency data stored in 33 (FIG. 5B) is sorted.

[0053] This sorting is performed, for example, as shown in FIG.
Electric field detection signal Ss checked in step 74
This is done in order of the level of the signal Ss, and in such a way that data of a frequency with a higher level of the signal Ss is placed at the beginning.

When this sorting is completed, the counter CT is set to "1" in step 79, and then the process returns to step 54 to wait for a key input again.

<<Changing AF station>> Select the channel from step 61 to
When changing to another broadcasting station of the same program searched in step 78, the change key Kc is pressed while waiting for key input in step 54.

Then, the process proceeds from step 54 through step 55 to step 56, and in this case, since the change key Kc has been pressed, the process further proceeds from step 56 to step 81.

[0057] Then, in this step 81, RA
Of the frequency data of M33 (Figure 6), Cth from the beginning
T-th frequency data AFD(i), in this case CT
= 1, the first data AFD(5) is extracted, and then in step 82, the frequency data AFD(i) extracted in step 81 and the count value CT
is supplied to the display controller 45, and the frequency indicated by the frequency data AFD(i) and the count value CT are digitally displayed on the display device 46.

In this case, AFD(i)=AFD(5),
Since CT=1, as shown in FIG. 7A, the data AFD (
5) The frequency “88.5MHz” and “BE
"ST 1" are displayed. That is, in this case, it is displayed that the frequency at which the level of the detection signal Ss is maximum is the best.

[0059] Then, in step 83, RA
Of the frequency data of M33 (Figure 6), Cth from the beginning
The broadcasting station of the data AFD(i) of the T-th frequency, that is, the broadcasting station displayed on the display device 46, is selected. In this case, the broadcasting station of AFD (5) is selected.

Subsequently, in step 84, the counter CT is incremented by "1" (the value CT is equal to RA
When the number of frequency data remaining in M33 exceeds CT=4 (in this case, CT=1), the process returns to step 54 and waits for key input again.

Therefore, in this state, the detection signal Sd
The broadcasting station whose frequency has the highest level is selected.

However, even if the detection signal Sd is at the highest frequency broadcasting station, if there is reception interference such as light interference that is not checked in items ① to ①, and the frequency is not suitable for reception, try again. , press change key Kc.

Then, the process proceeds from step 54 through steps 55 and 56 to step 81, but in this case, CT=2.

Therefore, in step 81, R
The second data AFD(1) of AM33 is taken out, and in step 82, as shown in FIG. 7B, the frequency “99.1 MHz” indicated by the data AFD(1) and the count value CT=2 are characters are displayed on the display device 46, and in step 83, the data AFD(1)
The broadcasting station with the frequency indicated by is selected.

Then, in step 84, the counter CT is incremented by "1", and in step 54, the process waits for a key input.

Thereafter, each time the change key Kc is pressed, steps 81 to 84 are repeated, and since the count value CT is incremented at this time, each time the change key Kc is pressed, the display device 4
6 changes sequentially and repeatedly as shown in FIGS. 6A to 6D, and the receiving frequency also changes to the displayed frequency.

[0067] Therefore, by pressing the change key Kc, the best broadcast can be selected when the listener actually listens to it.

[0068] In the above, the process is performed in step 7.
After step 9, the process may proceed to step 81.

[0069]

According to the present invention, it is possible to select broadcasting stations broadcasting the same program using the AF list. In this case, in particular, according to the present invention, the frequency data AFD ( CT) When selecting a broadcast station, press ■～■
Broadcasting stations with frequencies that pass all of the checks in section 1.1 are selected, and the station with the highest reception level is selected first, so you can be sure to select a broadcasting station with good reception. .

For example, if only items ① and ② are checked, the broadcast waves selected according to the AF list are RF
Even if there is interference such as intermodulation or multipath, the checks in items ① and ③ will pass, so a broadcasting station with poor reception may be selected, but according to this invention,
There is no such thing.

Moreover, according to the present invention, if there is a reception problem in the selected broadcast for some reason, the change key K can be pressed.
By pressing c, the broadcast with the next highest reception level will be selected from among the frequencies that have passed all of the checks in sections ■~■, so when the listener actually listens to it, the best broadcast will be selected. can be played.

[0072] Also, the frequency data AFD of the AF list
(CT) When checking the reception status of the broadcast station, ■
The checks in items ~■ are performed in this order, and if the result of a certain check is negative, the subsequent checks are skipped and the reception status of the broadcasting station of the data AFD (CT+1) of the next frequency is checked. Therefore, a broadcasting station with good reception conditions can be searched for in a short time, and the station can be quickly selected.

[Brief explanation of drawings]

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

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

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

FIG. 4 is a diagram for explaining reception frequencies.

FIG. 5 is a diagram showing an example of the contents of an AF list.

FIG. 6 is a diagram showing an example of a result of sorting an AF list.

FIG. 7 is a front view showing an example of a display state.

[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 14 Oscillation circuit 21 Detection circuit 22 A/D converter 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 ~ Kc operation keys K1 ~ K10 Channel selection key

Claims (1)

[Claims] Claim 1: In a receiver that retrieves an AF list from RDS data and selects broadcasting stations of frequencies indicated in this AF list, when receiving broadcasting of one frequency, broadcasting stations of frequencies of the AF list are selected. , and checks whether the selected broadcasting station is transmitting the above RDS data, and if the result of this check is that the above RDS data is being transmitted, the PI code of this RDS data is checked, As a result of this check, if the PI code matches the PI code at the time of receiving the broadcast of the one frequency, store data indicating the broadcasting station with which this PI code matches and the reception level of the broadcast wave, When this stored data is sorted in the order of the above-mentioned reception level and a predetermined key operation is performed, data indicating the above-mentioned broadcasting station is retrieved in order from the above-mentioned sorting result for each key operation, and the selected station is selected based on the retrieved data. A receiver designed to do this.