JPH1146130A - Receiver for data demodulation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain data processing with high reliability by receiving various data with an accurate reception signal frequency without intermediate frequency count in the case of receiving a broadcast that sends the various data such as identification data of a broadcast station like a radio data system RDS broadcast simultaneously with a main signal. SOLUTION: A signal received by an antenna 21 in the automatic searching is converted into an intermediate frequency signal F14 at a front end 22 and amplified by an intermediate frequency amplifier circuit 24 in an IF/MPX circuit 23. A memory 37 stores a reception signal frequency, a PI code and an AF list included in an RDS signal as preset data. When a broadcast is received strongly, data of the same PI code are stored in the memory 37 continuously and a PI code loop classification means 33 assembles the data in the same group, and an AF comparator means 35 discriminates effectively only the storage content whose reception signal frequency is coincident with the AF list and deletes the storage content included in the other same group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data demodulation receiver having a function of demodulating various data multiplexed to a main signal in an RDS broadcast or the like and capable of automatic channel selection.

[0002]

2. Description of the Related Art Conventionally, receivers for receiving broadcasts include:
There is a case in which an automatic tuning function is provided which sequentially changes a reception frequency and automatically selects a broadcast receivable under predetermined conditions. In a specific frequency band, the modulation format of a broadcast wave is constant, and a broadcast signal frequency is assigned to each broadcast station in a fixed frequency step. In a receiver having a local oscillator of a frequency synthesizer system using a phase locked loop (hereinafter abbreviated as “PLL”), the reception frequency is changed by a predetermined frequency step by digital control, and an intensity exceeding a reference level is obtained. When the broadcast is received, the change of the reception frequency is stopped, and the reception of the broadcast is continued, so that automatic channel selection, also called auto search, can be easily performed.

For example, European RDS (Radio Data System)
m) In broadcasting or the like, various data including broadcast station identification information and the like are transmitted in a multiplex system at the same time as a main signal modulated in the FM system. As the broadcast station information, PI (Prog
ramme Identification) code is transmitted, and AF (Alternative Fre
quency) list is also sent.

FIG. 3 shows a schematic electrical configuration of a conventional RDS receiver. The RDS broadcast signal received by the antenna 1 is input to the front end 2 at a reception signal frequency F12. In the front end 2, while amplifying the high frequency signal of the signal frequency F12, the intermediate frequency signal F14
Convert to The intermediate frequency signal F14 is input to the intermediate frequency amplification circuit 4 in the IF / MPX circuit 3, amplified, and detected by the detection circuit 5. The output of the intermediate frequency amplifying circuit 4 is also supplied to the tuning detecting circuit 6, and a tuning signal F16 is derived. The output of the detection circuit 5 is provided to a stereo demodulation circuit 7, and if the signal is a multiplexed (MPX) processed stereo signal, it is separated into left and right (LR) signals. IF / MP
The X circuit 3 thus includes the intermediate frequency amplification circuit 4, the detection circuit 5, the tuning detection circuit 6, and the stereo demodulation circuit 7,
It is manufactured as one analog semiconductor integrated circuit (IC). The output of the IF / MPX circuit 3 is provided to an RDS demodulation circuit 8, from which a data signal is extracted.

[0005] The reception signal frequency F12
Is converted from the PLL frequency synthesizer 9 to the intermediate frequency signal F14.
1 is generated. In the upper heterodyne method, the following first
There is a relationship as shown in the equation. F12 = F21-F14 [MHz] (1)

[0006] The frequency synthesizer 9 generates a local oscillation frequency signal F21 in a PLL system. In Europe where RDS broadcasting is performed, the frequency step of the broadcast signal is usually 5
Since the frequency is allocated in the 0 kHz span, the local oscillation frequency signal F21 is generated as represented by the following second equation, where N is the frequency division ratio. F21 = N × 0.05 [MHz] (2)

[0007] The intermediate frequency signal F14 is usually 10.7M.
Hz or the like is adopted, and is expressed by the following third equation from the first and second equations. F14 = N × 0.05−F12 [MHz] (3)

The change in the frequency of the frequency synthesizer 9 is
It is controlled by the microcomputer 10. In the microcomputer 10, tuning signal detecting means 11, which is realized by an operation according to a preset program,
An IF frequency counting unit 12, a division ratio changing unit 13, and an RDS signal detecting unit 14 are included. The operation result from the user to the preset key 16 is input to the microcomputer 10, and the automatic tuning result of the broadcast signal is stored in the memory 17. The result of the automatic channel selection stored in the memory 17 can be directly designated as preset data from the preset key 16.

FIG. 4 shows the microcomputer 10 of FIG.
Shows the automatic channel selection operation by. When the user operates the preset key 16, the operation of the automatic channel selection function is started from step a1. In step a2, the frequency division ratio N is initialized to a minimum value. In step a3, a local oscillation frequency signal F21 is generated according to the above-described second equation, and a broadcast received by the antenna 1 at a signal frequency F12 according to the first equation is selected. In step a4, the tuning signal detecting means 11
It is determined whether or not the tuning signal F16 exceeds a predetermined level. When the tuning signal F12 is detected to exceed the predetermined level, the microcomputer 10 sends an IF signal output request to the IF / MPX circuit 3 in step a5.

In step a6, the IF frequency counting means 12 counts the frequency of the intermediate frequency signal supplied from the intermediate frequency amplifier circuit 4 of the IF / MPX circuit 3, and determines whether or not the frequency is within the target tolerance. If the reception signal frequency F12 is stopped at the frequency WF-1 of the desired broadcast signal, the intermediate frequency signal F21 is correctly set to 10.7.
It should be MHz. However, when the broadcast signal is strong, the broadcast signal frequency is
In some cases, an IF signal of a sufficient level that can be detected as the tuning signal F16 even if the signal is greatly attenuated by the intermediate frequency amplifier circuit 4 or the like may be obtained. Therefore, the frequency WF-2 which is about one span before the frequency change of the automatic tuning or the frequency W which is one span too far
It may stop at F-3. In such a case,
As a means for confirming and correcting whether or not the frequency matches the correct broadcast signal frequency, if an IF signal request is received from the microcomputer 10, the IF / MPX circuit 3 outputs the intermediate frequency signal to the IF OUT which is a dedicated terminal. Is provided. The target tolerance of the IF signal frequency count is set to, for example, ± 0.04 [MHz] or less. The relationship between the reception frequency and the intermediate frequency at the time of the above-described automatic channel selection stop is expressed as in the following Table 1 from the third equation.

[0011]

[Table 1]

When the reception frequency is WF-2, it is determined that the frequency is lower than the specified range when the frequency is lower.
Then, the dividing ratio changing means 13 instructs the frequency synthesizer 9 to increase the dividing ratio N by N + 1, that is, 1. Conversely, when the reception frequency is WF-3, it is determined that the higher frequency is out of the specified range, and in step a7, the frequency division ratio changing means 13 reduces the frequency division ratio N by N-1, that is, 1 , And issues an instruction to the frequency synthesizer 9. After the division ratio change instruction in step a7, step a5
When an IF signal output request is made and the IF signal frequency count is performed in step a6, the intermediate frequency matches 10.7 MHz because the reception frequency is WF-1, which is within the target tolerance. Then, an instruction to stop the automatic search is issued from the microcomputer 10 to the frequency synthesizer 9, and the automatic search which is the automatic channel selection operation is stopped.

Next, at step a9, the RDS signal detecting means 14 of the microcomputer 10 determines whether or not the broadcast signal frequency contains an RDS signal. The RDS signal is a frequency component about 57 kHz away from the carrier frequency. If it is determined that it is included, the RDS signal is acquired in step a10, and
At 11, the reception frequency WF- 1 and the RDS signal at this time are stored in the memory 17. When no tuning signal is detected in step a4, or when registration in the preset memory in step a11 is completed, the frequency division ratio N is increased by 1 to N + 1 in step a12. Next, step a13
As long as it is determined that the frequency division ratio N is not larger than the maximum value, the operations from step a3 to step a13 are repeated. When the frequency division ratio N becomes larger than the maximum value, the automatic search is stopped at step a14. I do.

[0014]

An IF as shown in FIG.
The / MPX circuit 3 has a function of transmitting the intermediate frequency signal F14 in response to an IF signal output request, and has a dedicated IF signal transmission terminal. Therefore, the / MPX circuit 3 is very expensive and cannot be used for an inexpensive receiver. Have difficulty. Therefore, an IF / MPX semiconductor integrated circuit that does not have the function of transmitting the intermediate frequency signal F14 is used for a general low-priced receiver product. In this case, as described above, when the broadcast signal is strong, the auto search may stop at a frequency one span before or one span after. With a strong broadcast signal that stops tuning in auto search,
As long as a normal FM broadcast signal is received, it stops at a frequency one span before or one span after, and even if it is recognized as a broadcast signal and reception is continued, an audio signal is demodulated from a relative frequency change. There is no particular problem.

However, high stability is required to receive a broadcast including a long digital signal, such as European RDS broadcast, and to prevent malfunction during data reception. In addition, since the broadcast station name is displayed by the PI code included in the RDS signal, inconsistency occurs when the reception frequency does not match the broadcast station name. For this reason, reception at an incorrect broadcast signal frequency cannot be tolerated, and an expensive IF / MPX semiconductor integrated circuit having an intermediate frequency signal transmission function must be used.

An object of the present invention is to provide a data demodulation receiver capable of receiving a broadcast including data at an accurate reception signal frequency by automatic channel selection without counting an intermediate frequency signal. .

[0017]

SUMMARY OF THE INVENTION The present invention relates to a data demodulation receiver for receiving a broadcast in which a data signal including a main signal and broadcast station identification information and broadcast signal frequency information is transmitted. For each frequency step to be performed, scanning means for performing reception by sequentially changing the reception frequency, and for each reception frequency at which the reception of the broadcast is performed by sequentially changing the scanning means, storing whether or not the broadcast reception including data, When receiving a broadcast including data, storage means for storing broadcast station identification information and broadcast signal frequency information, and referring to the storage means when a broadcast is received at successive reception frequency steps changed by the scanning means. Stored contents having identification information of the same broadcasting station and having consecutive reception frequencies are grouped, and reception frequencies matching broadcast signal frequency information within the group are grouped. A data demodulation receiver, characterized in that it comprises a control means for controlling to perform a broadcast reception in a few.

According to the present invention, the scanning means performs reception by sequentially changing the reception frequency for each frequency step to which the broadcast signal frequency is allocated, and when the broadcast is received, the reception frequency and the broadcast including the data are transmitted. Information on whether or not to receive, and when receiving a broadcast including data, the identification information of the broadcast station and the broadcast signal frequency information are stored in the storage means. The control unit refers to the storage unit, has the identification information of the same broadcast station, groups storage contents having continuous reception frequencies, and performs broadcast reception at a reception frequency that matches broadcast signal frequency information within the group. Therefore, even if the broadcast signal is strong, it is possible to receive the broadcast at an accurate reception frequency and perform stable data processing.

Further, in the present invention, the control means deletes the storage contents corresponding to the reception frequency which does not match the broadcast signal frequency information from the grouped storage contents of the storage means.

According to the present invention, the broadcast is received corresponding to a plurality of reception frequencies, such as when the broadcast signal is strong, and the reception frequency is the broadcast signal frequency among the contents stored in the storage means. Since the stored contents in the group that does not match the information are deleted, the storage contents of the storage unit that stores the results of automatic channel selection are limited to only those that can reliably receive broadcasts, and accurate reception as a preset function It can be used effectively to select a channel by frequency.

In the present invention, the broadcast in which the data signal is transmitted is an RDS broadcast, and the storage means stores a PI code as identification information of the broadcast station and an AF list as the broadcast signal frequency information. It is characterized by the following.

According to the present invention, reception of RDS broadcast is
It can be performed accurately using a code or an AF list.

[0023]

FIG. 1 shows a schematic electrical configuration of a data demodulation receiver according to an embodiment of the present invention. The antenna 21 receives broadcast radio waves at the reception signal frequency F12. The signal received at the reception signal frequency F12 is amplified by the front end 22 and converted to an intermediate frequency signal F14. The intermediate frequency signal F14 is IF /
Amplified by the intermediate frequency amplifier circuit 24 in the MPX circuit 23,
The detection is performed by the detection circuit 25. The tuning signal F16 is generated by the tuning detection circuit 26. The output of the detection circuit 25 is demodulated by the stereo demodulation circuit 27 as a stereo signal.
The output of the IF / MPX circuit 23 is
Then, the data portion is demodulated. The local oscillation frequency signal F21 to be given to the front end 22 is generated by a frequency synthesizer 29. Such an antenna 21,
Front end 22, intermediate frequency amplification circuit 24, detection circuit 25, tuning detection circuit 26, stereo demodulation circuit 27, RD
The S demodulation circuit 28 and the frequency synthesizer 29 basically include the conventional antenna 1, front end 2, intermediate frequency amplification circuit 4, detection circuit 5, tuning detection circuit 6, stereo demodulation circuit 7, RDS demodulation circuit shown in FIG. 8 and the frequency synthesizer 9, and a duplicate description will be omitted.

The microcomputer 30 of the present embodiment
Are tuning signal detecting means 31, RDS signal detecting means 32 realized by a preset program operation, PI
It includes a code group classification unit 33, a memory determination unit 34, and an AF comparison unit 35. Microcomputer 30
Is input from the preset key 36 by the user. The tuning result of the automatic search operation by the microcomputer 30 is stored in the memory 37.

FIG. 2 shows the microcomputer 30 of FIG.
The operation means of the automatic search according to FIG. Step b1
The operation is started from step. In step b2, the value of the frequency division ratio N is set to the minimum value as an initial setting. The minimum value of the frequency division ratio N corresponds to the lower limit of the reception frequency band and is determined based on the above-described first and second equations. At step b3, a broadcast station is selected. When the broadcast is received, the intermediate frequency signal F
14 is amplified by the intermediate frequency amplifying circuit 24 and tuned to a broadcast station signal by the tuning detection circuit 26.
Is sent to the microcomputer 30. Step b
In 4, when the tuning signal F16 is detected at a predetermined level by the tuning signal detecting means 31, the automatic search is stopped. If the frequency division ratio N at this time is, for example, N = 1974, the reception frequency signal F12 at the time of stoppage is 88 MHz from the above-described first and second equations.

Next, at step b5, the detection signal F15 is sent from the detection circuit 25 to the RDS demodulation circuit 28, and the RDS signal is demodulated. The RDS signal is taken into the microcomputer 30, and it is determined whether or not the RDS signal is detected in the broadcast signal by the RDS signal detecting means 32.
If the RDS signal is detected, the data contained in the RDS signal is captured in step b6, and the PI code which is the broadcast station identification information and the A which is the broadcast signal frequency information are obtained.
The F list is temporarily stored. In step b7, it is determined whether or not there is a broadcast reception stored in the memory 37 at a frequency division ratio of N-1 corresponding to one span before. If there is a memory at the dividing ratio of N-1, it is determined in step b8 whether or not the same PI code is used. In step b7, the dividing ratio N-
If it is determined in 1 that there is no storage of broadcast reception, or if it is determined that the PI codes are not the same, the parameter G representing the group number is increased by 1 in step b9.

When the broadcast signal is strong, the signal is detected at a signal level that can be sufficiently received even at a frequency that is about one span before or one span behind the original broadcast signal frequency, and the tuning signal F16 is obtained. Since it is detected, the frequency 88 MHz stopped by the current auto search cannot be determined to be the original broadcast signal frequency.
Therefore, step b7, step b8 and step b
PI code group classification means 33 represented by operation 9
However, the channel selection result having the continuous frequency division ratio N is regarded as one group, and the same group number G is assigned. That is, when there is no channel selection result in the division ratio N-1 or when the GI code is not the same, the group number G is incremented by 1 in step b9, and the same PI is stored in the storage contents of the continuous division ratio. Group number G if code
Are the same.

In step b8, the PI code is set to the dividing ratio N-1.
When it is determined to be the same as above, or when the process of step b9 is completed, the process proceeds to step b20. Step b
If no tuning signal is detected in step 4, or step b5
Also, when the RDS signal is not detected in step b20, the process proceeds to step b20. In step b20, it is determined whether or not the storage content corresponding to the frequency division ratio N-1 is stored in the memory 37. When it is determined that the division ratio N-1 has stored contents,
That is, when the broadcast is being received at the continuous frequency division ratio, it is determined in step b21 whether the same PI code is stored with the parameter M = 0. When the condition is satisfied, it is determined in step b22 whether or not the group belongs to a different PI code. When the condition is satisfied,
In step b23, the AF list is compared with the contents stored in the memory 37. If they match, step b24
In step b25, the value of the parameter M is increased by 1.
Then, it is determined whether or not there is a tuning result stored in the memory 37 in a group having the same PI code. In some cases, in step b26, other channel selection results in the same group are deleted, and the process returns to step b25. Step b2
If it is determined in step 5 that there is no stored content in the same group, the process returns to step b21. When the condition is not satisfied in step b20, step b21, step b22, and step b23, the process proceeds to step b30.

In the operation from step b20 to step b26, as the operation of the AF comparing means 35 in the microcomputer 30, which of the same group of continuous reception frequency spans is the reception result of the original broadcast signal frequency. Then, in step b24, the memory determination means 34 of the microcomputer 30 increases the value of the parameter M by one. The parameter M is usually M = 0, as described later, and the operation in step b24 is M = 1.
Operation. Other received frequency signals in the same group of continuous spans stored in the memory 37 are determined not to be the original broadcast signal frequencies, and
7 is erased from the stored contents.

At step b30, N,
The data of the PI code, the AF list, and the parameters G and M are written. Next, in step b31, M is reset to 0, and N is increased by 1 in step b32. In step b33, it is determined whether or not the frequency division ratio N exceeds the maximum value.
If not, the process returns to step b3. Dividing ratio N
Exceeds the maximum value, the automatic search is terminated in step b34. Note that G = 0 and M = 0 are also set at the time of the initial setting in step b2.

When the operation shown in FIG. 2 is performed for the first time, since the frequency division ratio N is the minimum value in step b2, the frequency division ratio N-
1 does not exist, and steps b7 to b
At 9, the group number is G = 1. In step b20, since the memory determination code M is undetermined and M = 0, and the frequency division ratio N is the minimum value, the process proceeds from step b20 to step b30. Hereinafter, it is assumed that the process returns from the step b30 to the step b3 via the step b33, and the memory table as shown in the following Table 2 is stored in the memory 37.

[0032]

[Table 2]

As shown in Table 2, area 1 of memory 37
Stores the tuning result received when the frequency division ratio N is 1974. Next, from step b3 to step b6 after the division ratio N becomes 1975 in step b32 of FIG. 2, the division ratio N of the area 1 is exactly the same as 1974. In step b7, since there is the memory content of the dividing ratio N-1, that is, N = 1974 in this case, the process proceeds to step b8, and since the PI code is also the same, the group number G is set to G as in the area 1. = 1.
In step b20, the dividing ratio N-1 is N = 1974.
Since there is an area 1 which is the storage content of the above, and in step b21, there is the same PI code with M = 0, so step b22
Proceed to. However, PI between area 1 and area 2
Since the code groups are the same, step b
Proceeding to 30, the contents of area 2 of Table 2 are transferred to memory 37.

In the case of area 3 in Table 2, since the operation is exactly the same as that of area 2, the description is omitted. The storage contents of the areas 4, 5, and 6 are the storage contents in which the value of the frequency division ratio N is slightly apart from the areas 1, 2, and 3. In the auto search, the broadcast signal is not received for a while and the scanning of the frequency is stopped. This is a reception signal detected after the state of not performing. Also, the PI code is different from the areas 1, 2, and 3. Area 4
Is the same as that of the areas 1, 2, and 3 from step b3 to step b6, but at step b7, the memory 37 corresponding to the division ratio N-1, ie, the division ratio N = 1979, is stored in the memory 37. Since there is no content, step b
At 9, the group number G increases by 1 and G = 2. As a result, a group number different from areas 1, 2, and 3 is assigned. The contents of the processing for the areas 5 and 6 are the same as those of the area 4, and the description is omitted.

Next, in the case of reception corresponding to the areas 7 and 8, the frequency division ratio N also takes a value slightly apart from the areas 4, 5 and 6. The PI code is the same as the group number G = 1, that is, the areas 1, 2, and 3, and is different from the areas 4, 5, and 6.

First, the area 7 will be described. From step b3 to step b9, the processing is the same as that of the area 4, except that the group number G = 3, so that the description is omitted. Also in the area 8, similar to the area 7, the processing is the same as that of the areas 5 and 6, except that the group number G = 3, so that the description is omitted.

At step b30, the channel selection results determined at steps b2 to b9 and steps b20 to b26 are transferred to the memory 37. In step b31, the memory determination parameter M is replaced with an initial value, that is, M = 0 meaning indefinite. Step b32
Then, the frequency division ratio N is set to N + 1, and the process is advanced by one. At step b33, it is determined that the processing routine is stopped when the frequency division ratio N reaches the maximum value.

The effect of the present invention is most remarkable when it is assumed that the tuning signal F16 is not detected at the next division ratio N = 1985 of the area 8, which will be described below. First, in step b4, since the tuning signal F16 is not detected, the process proceeds to step b20. Since the storage content corresponding to the frequency division ratio N-1, that is, N = 1984 exists in the area 8, the process proceeds to step b21. In step b21,
The memory fixed number M = 0, that is, means uncertain, and it is determined whether the group numbers G are different and the same PI code is present. As can be seen from FIG. 2, areas 1, 2, 3 where the PI group is G = 1 and the PI group is G
Areas 7 and 8 where = 3 correspond to the determination target in step b21. Therefore, in step b23, the broadcast signal frequency of the AF list held in the area 8 stored last and the reception signal frequency calculated from the frequency division ratio stored in the areas 1, 2, 3 of the memory 37 are compared. I do. For example, if a broadcast signal frequency of 88.05 MHz is present in the AF list in area 8, the broadcast signal frequency F12 = 19 calculated from the division ratio 1975 of area 2
75 × 0.05-10.7 = 88.05 MHz. That is, 88.05 MHz held in area 2
Is on the AF list, it is clear that the broadcast signal frequency is correct, and in step b24, the area 2
Is changed from 0 to 1 to clarify that the stored contents are determined.

Next, at step b25, it is determined whether or not there is another storage content having the same group number G = 1 as that of the area 2. As described above, when a strong broadcast is received, it is considered that the possibility that the tuning signal F16 is detected at an erroneous received signal frequency is also increased. Even if the frequency is the same, the broadcast signal in the area 2 and the content of the broadcast are the same, and there should be no problem even if the broadcast signal is deleted. Therefore, the areas 1 and 3 corresponding to this are deleted. Next, the process returns to step b21 again, and it is determined whether M = 0 and the same PI code exists. This time, areas 7 and 8 viewed from area 2 correspond to this. In step b23, area 2
Assuming that 88.45 MHz is obtained in the AF list, for example, it can be understood that the area 7 corresponds from the frequency division ratio N of the area 7 = 1983. That is, F12 = 19
83 × 0.05-10.7 = 88.45 MHz. Therefore, in step b24, it is determined that the area 7 has the stored content having the correct broadcast signal frequency, and M = 1 is determined. In step b25 and step b26, step b21 which is the storage content of the same group is deleted. Here, even if the process returns to step b21 again, since there is no stored content having the same PI code at M = 0, the process proceeds to step b30, where the content determined in the previous steps is transferred to the memory 37, and The procedure from step b3 to step b33 is repeated until the value becomes maximum.

That is, in the RDS receiver, when the preset key 36 is operated, the receiving frequency is changed at every predetermined step, and the tuning signal detecting means 31 which is generated when a broadcast signal is received by this scan, R for signal
When a plurality of PI codes included in the RDS signal are detected in the same and consecutive spans, the received signal frequency is determined to be the same group. The result determined by the PI group determination unit 33 is transferred to the memory 37. After that, when the AF comparison means 35 determines that the broadcast signal frequency is the correct broadcast signal frequency from the storage contents of the memory 37 having the same PI code and continuous spans,
The other stored contents of the same group are determined to be erroneous reception frequency signals, and are erased to perform correct channel selection. The memory 37
Performs a battery backup or the like, and retains the stored preset data even after the power of the data demodulation receiver is turned off, so that the preset key can be directly designated by the preset key 36 in the subsequent channel selection.

[0041]

As described above, according to the present invention, the intermediate frequency signal can be counted without using the broadcast station identification information and the broadcast signal frequency information of the data broadcast together with the main broadcast. Therefore, the reception signal frequency can be accurately matched with the broadcast signal frequency, and the data can be reliably received and the data processing can be performed.

According to the present invention, when a broadcast from the same broadcast station is received at a plurality of continuous frequencies, such as when the broadcast reception is performed strongly, the broadcast signal frequency information Since the storage contents that do not match the above are erased, the storage contents of the storage means are only the channel selection results in which the reception frequency exactly matches the broadcast signal frequency, and the reception of the broadcast can be performed by effectively using the storage contents.

Further, according to the present invention, the automatic tuning of the RDS broadcast can be reliably performed using the PI code and the AF list.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic electrical configuration of an embodiment of the present invention.

FIG. 2 is a flowchart showing a procedure of an automatic search by the microcomputer 30 of the embodiment of FIG.

FIG. 3 is a block diagram showing a schematic electrical configuration of a conventional RDS receiver.

4 is a flowchart showing an operation of an automatic search by the microcomputer 10 of FIG.

[Explanation of symbols]

 Reference Signs List 20 data demodulation receiver 21 antenna 22 front end 23 IF / MPX circuit 24 intermediate frequency amplification circuit 25 detection circuit 26 tuning detection circuit 28 RDS demodulation circuit 29 frequency synthesizer 30 microcomputer 31 tuning signal detecting means 32 RDS signal detecting means 33 PI Code group classification means 34 Memory determination means 35 AF comparison means 37 Memory

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04H 1/00 H04H 1/00 C

Claims (3)

[Claims] 1. A data demodulation receiver for receiving a broadcast in which a data signal including broadcast station identification information and broadcast signal frequency information together with a main signal is transmitted. Scanning means for sequentially changing the reception, and for each reception frequency at which a broadcast is received by sequentially changing the scanning means, stores whether or not a broadcast including data is received, and when receiving a broadcast including data, Storage means for storing the broadcast station identification information and broadcast signal frequency information; and when the broadcast is received at successive reception frequency steps changed by the scanning means, the storage means is referred to for identifying the same broadcast station identification information. It is possible to group stored contents having continuous reception frequencies and perform broadcast reception at a reception frequency that matches broadcast signal frequency information within the group. Control means for controlling the data demodulation. 2. The control unit according to claim 1, wherein the control unit deletes, from among the grouped storage contents of the storage unit, storage contents corresponding to a reception frequency that does not match broadcast signal frequency information. Data demodulation receiver. 3. The broadcast through which the data signal is transmitted is RD.
3. The reception for data demodulation according to claim 1, wherein the storage means stores a PI code as identification information of the broadcast station and an AF list as the broadcast signal frequency information. Machine.