JPH06326562A - Substitute station searching method - Google Patents

Abstract

PURPOSE:To search for a substitute station without malfunction. CONSTITUTION:At the outset, a turning control part 11d successively changes the tuning frequency of a front end 3 based on an AF list demodulated by an RDS decoder 8 each time the receiving state of the present receiving station is deteriorated. Then a substitute station is searched in the same program network, and a substitute station information registering part 11e registers the frequencies of both a previous receiving station and the searched substitute station in a substitute station memory 11c so that the relationship is known between the adjacent stations in the same program network. If the receiving state of a certain receiving station is deteriorated, the part 11d preferentially searches for the frequency that is registered as the adjacent station frequency in the same program network for some corresponding receiving station in the memory 11C. If this searching operation is impossible, the tuning frequency of the end 3 is successively changed by referring to the AF list demodulated by the decoder 8. Then a substitute station is searched in the same program network.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alternative station searching method, and more particularly to an information multiplexing alternative station searching method for multiplexing various data including information on an alternative station of the same program network in an FM broadcast.

[0002]

2. Description of the Related Art In a car radio, it is convenient to be able to automatically retune to a new station that is broadcasting the same broadcast when a vehicle moves out of the broadcast area while receiving a broadcast. is there. In order to realize this function, RDS (Radio Data System) has been proposed and put into practical use by the European Broadcasting Union.

This RDS is for multiplexing various digital data on an FM broadcast signal and transmitting it. The transmitted message is (1) Program identification code (PI) (PI) of the currently received FM broadcast. 2) Program name (PS) (3) Frequency list of the same program network (A
F) (4) Program content identification code (PTY) (5) Transmission status identification code (DI) (6) Music or conversation identification code (M / S), and (7) Traffic information broadcasting station identification code ( (TP) (8) There is an identification code (TA) etc. in the traffic information broadcast.

Thus, the F received by the RDS is
Since messages related to M broadcasting are transmitted in multiplex, it is possible to perform a special operation that has never been done by using the messages. For example, if the electric field strength of the receiving broadcasting station drops below a certain level due to the movement of the vehicle, the AF list is used to automatically send to another station in good reception that is broadcasting the same program. You can switch.

[0005]

By the way, the AF list
As shown in FIG. 13, the station D currently receiving is₀(Frequency f
_D0) Same program network PI_DAlternative station D
₁~ D_nFrequency f_D1, F_D2, ..., f_DnIs included
For some of these, for example, f
_D1It happens to be another program network PI like_E
The station D₀And station E, which partially overlaps the broadcasting area
₀Frequency f_E0May be consistent with. in this case,
Vehicle is station D₀AF list because it was out of the broadcasting area
When searching for an alternative station with reference, f_D1= F_E0Is a list
Since it is in the station E₀Will also be searched
Yes, a malfunction sometimes occurred. Bureau E₀Tuned to
And the station E₀PI code in RDS data received from
Station D that was receiving₀Is it the same as the PI code of
If you check it, it will not match.
Alternate station frequency f_D2~ F_DnTo continue the search with
And the user has to wait a long time until the search is completed.
Along with that, when you temporarily hear another program
The problem arises.

In order to solve this problem, as shown in FIG.
Initially, the vehicle has a certain program network PI_F
Station F that composes₀(Frequency f_F0) While receiving
Station F ₀AF list was used because it was out of the broadcasting area
Alternate station F by alternate station search₁(PI code = PI_F,frequency
Number f_F2), When you switch to the memory, PI_FCorresponding to
Attach f_F0And f_F1Is registered, and station F₁Service d
Since it is off the rear, an alternative station search using the AF list
Alternate station F₂(PI code = PI_F, Frequency f_F2) Cut into
When changed, PI is added to the memory_FAssociated with f_F2Add
Each receiving station F that followed automatically, such as additional registration
₀, F₁, F₂, F₃Frequency f of_F0, F_F1, F
_F2, F_F3, ... are registered. Other program networks
Network PI_G, PI_H, ... About multiple stations
Even when automatically following the order, the program network
Frequency f of each receiving station_G0，
f_G1, F_G2, F_G3, ..., f_H0, F_H1, F_H2, F_H3，
..., ... is registered.

[0007] Thereafter, for example, while receiving station F _2, when the reception state for off-broadcasting area of the vehicle station F ₂ has deteriorated, in memory, to configure the same program network PI _F and the station F ₂ It is checked whether some station frequencies have been registered, and if they are registered, these are given priority to search for an alternative station, and only when the alternative station cannot be found, the AF list received from the station F ₂ is referred to. There is a proposal to search for an alternative station. If the registered contents of the memory are as shown in FIG. 14 in advance, when the vehicle moves from the F ₂ to the F ₃ broadcasting area through the route e in FIG. 14,
Since f _F3 is registered in the memory, it is possible to quickly switch to the alternative station F ₃ without referring to the AF list.

However, even in the improvement plan in which the use of the AF list is minimized as described above, the program network PI _F registered in the memory is configured as follows.
For example the frequency f _F0 station F ₀ is the station F ₂ and overlapping broadcast area part, is to be consistent with the station frequency f _G0 stations G ₀ of the program network PI _G. In this case, when the vehicle travels through the route g in FIG. 14,
When the alternative station search is performed by referring to the memory when the station F ₂ deviates from the broadcast area, the station G ₀ is erroneously selected as a search target, which is not so useful for improving the malfunction.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a radio receiver capable of executing a search for an alternative station without malfunction.

[0010]

According to the present invention, the above-mentioned problems are initially solved every time the current reception condition of the receiving station deteriorates.
A means for searching for an alternative station of the same program network by referring to the AF list included in the FM broadcast signal, and a frequency of the receiving station that has been received until then and the alternative station after the search is completed are the adjacent stations in the same program network. Means for registering in a memory so that they are related to each other, and subsequently, when the receiving state of a certain receiving station deteriorates, the certain receiving station is stored in the memory as an adjacent station in the same program network. Means for preferentially searching for a station registered as, and when the means is unsearchable, it refers to the AF list included in the FM broadcast signal to search for an alternative station of the same program network and receive until then. The frequency of the receiving station and the frequency of the alternative station after the search are already in the same program network as adjacent stations. Is achieved by means for registering in the memory in association As can be seen.

[0011]

According to the present invention, initially, every time the current reception condition of the receiving station deteriorates, the AF list included in the FM broadcast signal is referred to search for an alternative station of the same program network, and until then. The frequencies of the receiving station that was receiving and the alternative station after completion of the search are related and registered in the memory so that it can be seen that there is an adjacent station relationship in the same program network, and then the receiving status of a certain receiving station. When the condition becomes worse, the station registered in the memory as a neighboring station in the same program network with respect to the certain receiving station is searched with priority, and when the search is impossible, the AF list included in the FM broadcast signal is referred to. Then, while searching for alternative stations in the same program network, the frequency of the receiving station that was previously received and the alternative station frequency after completion of the search are set to the same frequency. And related as it can be seen that an adjacent station relation is registered in the memory in the program network.

As a result, when the receiving condition of a certain receiving station deteriorates, a station registered in the memory as an adjacent station in the same program network with respect to the certain receiving station is preferentially searched. Since the adjacent station is not a station that constitutes another program network,
The frequency of accidentally temporary set tunes to other program networks during alternate station searches is significantly reduced, especially
When the vehicle travels on the route that it has traveled in the past, it can automatically follow the alternative stations one after another without any malfunction, and the broadcast is interrupted for a long time until the search is completed, or other programs temporarily. Is no longer heard.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall block diagram of an RDS radio receiver embodying an alternative station search method according to the present invention. Reference numeral 1 is an antenna, 2 is a PLL circuit for converting frequency control data into a corresponding control voltage, 3 is a front end, and a broadcast signal of a frequency corresponding to the control voltage input from the PLL circuit 2 is extracted from an antenna received signal, Converts to an intermediate frequency signal and outputs. 4 is an intermediate frequency amplification / detection circuit (IF /
DET circuit), which amplifies the intermediate frequency signal and performs FM detection. Reference numeral 5 is an MPX, which demodulates the FM detection signal into a stereo signal. Reference numeral 6 is an amplifier (AMP), and 7 is a speaker.

An RDS decoder 8 demodulates the RDS data superimposed on the FM detection signal. Reference numeral 9 denotes a signal meter, which detects the received electric field strength by performing DC detection on the intermediate frequency signal output from the intermediate frequency amplification / detection circuit 4. 10 is a station detector, which is within the range of the frequency deviation Δf (bandwidth) of the received signal,
In addition, when the received electric field strength is equal to or higher than a predetermined level, it is determined that there is a receiving station, and the high level station detect signal SD is output. That is, when the station detect signal SD is at a low level, even if the received electric field strength detected by the signal meter 9 is large, there is no broadcasting station at the tuning point, and the detected received electric field strength has an influence on the adjacent station. Judge that it has been received.

Reference numeral 11 denotes a controller having a microcomputer structure for controlling the overall operation of the RDS receiver, and reference numeral 12 denotes an operation section for performing various operations such as tuning operation for the RDS receiver. The structure of the controller 11 will be described. 11a is a buffer memory for storing RDS data (PI, AF, TP, TA, etc.), and 11b is an R demodulated by the RDS decoder 8.
Data registration unit for registering DS data in the memory 11a, 1
An alternate station memory 1c is an alternate station memory that stores, for each program network, the frequency of an adjacent station in association with the frequency of the station for each station forming the same program network. The stored data can be saved even after the power is turned off by using the stored SRAM.

Reference numeral 11d is a tuning control unit, which generates frequency control data corresponding to a reception frequency desired by the user and outputs it to the PLL circuit 2 to tune to a desired station when the operation unit 12 performs a tuning operation. . Also, while receiving a certain station, the output of the signal meter 9 is monitored, and when the received electric field strength falls below a certain level, it is determined that the reception state has deteriorated, and the AF list stored in the buffer memory 11a is detected. Or
By referring to the station frequency adjacent to the receiving station in the same program network as the current receiving station registered in the alternate station memory 11c, frequency control data for searching for the alternate station are sequentially generated, and the PLL circuit 2 By switching to the reception frequency by outputting to the station, a station with the same program network as the station that has been receiving until then is detected, and the reception frequency is fixed when the reception electric field strength exceeds a certain level. Controls station search.

Reference numeral 11e denotes an alternative station information registration unit, which, when a search for an alternative station is performed using the AF list, sets the frequencies of the station that has been received until then and the frequency of the alternative station after the search are the same as each other in the same program network. Are registered in the alternative station memory 12c in association with each other so that it can be seen that they are in the adjacent station relationship.

FIG. 2 shows the data registered in the alternative station memory 12c.
FIG. By Program Network (PI
Code = PI_A, PI_B, PI_C, ...)
Identify each station received in one program network
Receiver frequency f for_A0, F _A1, F_A2, F_A3・ ・ ・ ・ ・ ・
f_B0, F_B1, F_B2, F_B3, ..., f_C0, F_C1, F_C2，
f_C3,,, ... are registered and
Within the same program network for each receiving station frequency
The frequencies of adjacent stations are registered. For example, f _A0And f_A1
Are in an adjacent station relationship within the same program network
The receiving station frequency f_A0Corresponding to the adjacent station frequency f_A1But
Registered, conversely, the receiving station frequency f_A1Corresponding to the adjacent station
Frequency f_A0Is registered. Also, f_A1And f_A2Are the same professional
When there is an adjacent station relationship in the Gram network, the receiving station
Frequency f_A1Corresponding to the adjacent station frequency f_A2Is registered,
Conversely, the receiving station frequency f_A2Corresponding to the adjacent station frequency f_A1
Is registered.

FIG. 3 shows an example of an RDS data format which is transmitted by being superimposed on an FM broadcast signal. FIG. 3 is a type 0A group for transmitting RDS data related to the program network of the FM broadcast signal itself. Among the four blocks, the first block is PI (TN), the second block is a group address, and TP is a group address. (TN), PTY (TN), TA (TN)
In the third block, two AFs (TN) are sent, and in the fourth block, two characters of PS (TN) are sent. Note that (TN)
Indicates that it relates to the program network of the FM broadcast signal itself.

FIGS. 4 to 8 are flow charts for explaining the operation of the controller 11, FIGS. 4 to 7 show a main flow, and FIG. 8 is executed when RDS data is output from the RDS decoder 8. Indicates interrupt processing. FIG. 9 is an explanatory diagram showing the relationship between the traveling route of the vehicle and the broadcasting area of each broadcasting station, and FIGS. 10 to 12 are explanatory diagrams of the alternative station data registered in the alternative station memory 12c. Hereinafter, description will be given with reference to these figures. In FIG. 9, A _{0 to} A ₄ are broadcasting stations of the respective frequencies f _{A0 to} f _A4 forming the same program network PI _A , and B _{0 to} B ₂ are the same program network PI.
It is a broadcasting station of each frequency f _{B0 to} f _B2 that constitutes _B. It is assumed that the vehicle travels on routes a, b, c, and d after the set is turned on. Note that it is assumed that data has not been recorded in the alternative station memory 12c at first.

When the power switch is turned on, the tuning controller 11d performs a predetermined initialization process (step 1 in FIG. 4).
01), the frequency control data related to the broadcasting station received immediately before the power-off last time is output to the PLL circuit 2, and the reception state immediately before the power-off last time is reproduced. Here, the set is station A ₀
Tuning to, and the conversion, the vehicle is assumed to be contained within the broadcast area of the station A _0, the intermediate frequency signal with FM broadcast signal station A ₀ in the front end 3 is taken out from the received signals of antenna 1 To be done. And intermediate frequency amplification /
The detection circuit 4 performs amplification and detection, and the multiplexer 5 demodulates the stereo audio signal. This audio signal is amplified by the amplifier 6 and then acoustically reproduced by the speaker 7.

The RDS data superimposed on the FM broadcast signal is sent from the broadcasting station A ₀ , demodulated by the set RDS decoder 8 and output to the controller 11 (see FIG. 2).
When the RDS data is output from the RDS decoder 8, the controller 11 executes the interrupt process of FIG. 8, inputs the RDS data, and checks whether the alternative station is currently being searched. Since it is NO, the data registration unit 11b is stored in the buffer memory 11a. R such as PI, AF, PTY, TP, TA, PS
The DS data is registered (steps 501 to 503). When the RDS data is input during the alternative station search, the controller 11 inputs the PI code to the tuning control unit 11d (steps 502 and 504).

Station A₀Tuning of controller 11 during reception of
At any time, the control unit 11d performs a tuning operation on the operation unit 12.
Also, the received electric field strength input from the signal meter 9
The received electric field strength indicated by the signal is below a certain level and the current receiving station
Is being monitored to see if it has deteriorated (step in Fig. 4
102, 103). The vehicle runs along the line a in Figure 9,
A₀Station A as well as out of the broadcasting area₀Same as
Program network PI_AStation A that composes₁Broadcast of
Enter the rear station A₀If the reception condition of the
It is determined to be YES in 103. At this time, first, the alternative station
Program network PI on memory 12c_AInformation about
Check if information is registered (step 104),
Since it is initially NO, the buffer memory 11a is set to 1 → i.
Station A registered in₀Of the AF list received from
i-th alternative station frequency data AF ₀Read out
Generates frequency control data and outputs it to the PLL circuit 2,
Wait a certain time until the PLL circuit 2 locks up,
AF₀(Steps 105 to 108).

Then, it is checked whether the station detect signal SD input from the station detector 10 is at a high level to detect a station (step 2 in FIG. 5).
01), the process proceeds to step 205 if NO, and if YES, the PI code demodulated by the RDS decoder 8 (see FIG. 8).
Is input to the tuning control unit 11d in step 504 of step 504), it is checked whether it is the same PI _A as the station A ₀ which has been receiving (step 202). If NO, the process proceeds to step 205.
If YES, the received electric field strength signal is input from the signal meter 9 to temporarily store the received electric field strength, and it is checked whether the electric field strength is above a certain level (steps 203 and 204). If NO, the routine proceeds to step 205. In step 205, AF
It is checked whether or not the processing has been completed for all the alternative stations included in the list, and if the result is NO, i is incremented (step 206) and the process returns to step 106 of FIG.
The next alternative station frequency data AF ₁ in the F list is read out, corresponding frequency control data is generated, and the PLL circuit 2 is generated.
To the AF ₁ and wait for a fixed time until the PLL circuit 2 locks up, and tunes to AF ₁ (steps 107, 10).
8).

Then, the processing from step 201 onward in FIG. 5 is executed to check whether the station detect signal SD input from the station detector 10 is high and a station is detected. If NO, the routine proceeds to step 205, where YES is determined. Then the PI demodulated by the RDS decoder 8
It is checked whether the code is the same PI _A as the station A ₀ that has been receiving until then (step 202), and if NO, step 205
If YES, the received electric field strength signal is input from the signal meter 9 to temporarily store the received electric field strength, and it is checked whether the electric field strength is above a certain level (steps 203 and 204).
If NO, the process proceeds to step 205. In step 205, it is checked whether or not the processing has been completed for all the alternative stations included in the AF list. If NO, i is incremented (step 206) and the process proceeds to step 106 of FIG. 4 again.

In this way, while tuning the sets sequentially for the alternative stations included in the AF list, the station detected and the alternative station whose PI code is PI _A has a received electric field strength above a certain level. If there is any, the determination is YES in step 204 of FIG. 5, the frequency is fixed to the reception frequency at that time, and the search for the alternative station is completed. AF without being YES in step 204
When the processing is completed for all the alternative stations included in the list and YES is obtained in step 205, the frequency control data related to the alternative station having the highest received electric field strength in the AF list is output to the PLL circuit 2. Then, the reception frequency is fixed to the alternative station and the alternative station search is completed (step 207).
Here, when the station A ₁ is tuned to, Y is returned in step 204.
If it becomes ES, the reception frequency is fixed to the station A ₁ , so that the program of the program network PI _A can be continuously listened to.

When the alternative station search is performed using the AF list in this way, the alternative station information registration unit 11e checks whether or not there is a registration area of the program network PI _{A in} the alternative station memory 11c (step of FIG. 6). 301), NO
Therefore, the registration area is created (step 302, FIG. 10).
(See (1)). Then, the frequencies f _A0 and f of the stations A ₀ and A ₁
Both _A1 are registered as the receiving station frequency, and the receiving station A ₀
F _A1 is registered as the adjacent station frequency of the receiving station A ₁ , and f _A0 is registered as the adjacent station frequency of the receiving station A ₁ (steps 303 and 30).
4). As a result, the frequencies of the two stations A ₀ and A ₁ forming the program network PI _A are registered in the alternative station memory 11c in association with each other so that it can be seen that the frequencies are adjacent to each other in the same program network. (See FIG. 10 (1)).

The RDS data sent from the station A ₁ on the FM broadcast signal is demodulated by the RDS decoder 8 and then
The data is registered in the buffer memory 11a by the data registration unit 11b of the controller 11 (steps 501 to 5 in FIG. 8).
03). Thereafter, the vehicle that has traveled along a 9, station A ₁ station A ₁ enters the broadcast area of the station A ₂ constituting the same program network PI _A and station A ₁ together out of the broadcast area If the reception state of is deteriorated, the tuning control unit 11d again determines YES in step 103 of FIG. At this time, first, it is checked whether or not the information about the program network PI _A is registered in the alternative station memory 12c (step 104), and since it is YES this time, the station A ₁ currently receiving as the receiving station frequency in the program network PI _A. It is checked whether the frequency f _{A1 of} is registered (step 401 in FIG. 7).

Since the determination here is also YES, the tuning controller 11d
Is set to 1 → j, and the station A ₁ of the frequency f _A1 currently being received in the program network PI _A from the alternative station memory 11c
The j (= 1) th adjacent station frequency f _A0 for the PLL circuit 2 is read, and corresponding frequency control data is generated to generate the PLL circuit 2
To the PLL circuit 2 and waits for a fixed time until the PLL circuit 2 locks up, and tunes to f _A1 (steps 402 to 40).
5). Then, it is checked whether the station detect signal SD input from the station detector 10 is at a high level and a station is detected (step 406). Since the answer is NO here, the routine proceeds to step 409.

If YES in step 406, the received electric field strength signal is input from the signal meter 9 to temporarily store the received electric field strength, and it is checked whether the electric field strength is above a certain level (steps 407 and 408). For example, the search for the alternative station is completed while fixing the reception frequency at that time, but if NO, the process proceeds to step 409.

In step 409, the program network PI _A registered in the alternative station memory 11c checks whether or not the processing has been completed for all adjacent station frequencies relating to the station A _1. Since YES is obtained here, each tuned this time is then checked. It is checked whether or not a station is detected among the frequencies of the adjacent stations (step 410), and since it is NO, the process proceeds to step 105 onward in FIG.

After step 105, the station is detected and the PI code is set to PI _A while the set is sequentially tuned for the alternative stations included in the AF list received from the station A _{1 first.}
Check if there is an alternative station whose received electric field strength is above a certain level, and if there is, determine YES in step 204 of FIG. 5 and fix it to the receiving frequency at that time. Finish the search for the alternate station. Step 204
Processing is completed for all the alternative stations included in the AF list without being YES in step 205, and if YES in step 205, frequency control is performed for the alternative station having the highest received electric field strength in the AF list. The data is output to the PLL circuit 2, the reception frequency is fixed to the alternative station, and the alternative station search is completed (step 207). Here, station A ₂ is searched as an alternative station, so program network P
The program of I _A can be continuously listened to.

In this way, the alternative station is used by using the AF list.
When the search is performed, the alternative station information registration unit 11e displays the alternative station.
Program network PI in memory 11c_ARegistration area
Check if there is an area (step 301 in FIG. 6), and YE
Since it is S, the program network PI_AReceiving at
Station A that was previously received as the receiving station frequency₁Frequency f _A1
Check if was registered (step 305),
This is also YES, so this alternative station A₂Frequency f_A2To
Registered as a new receiving station frequency and receiving station frequency
f_A1F as the adjacent station frequency of_A2Register the receiving station frequency
f_A2F as the adjacent station frequency of_A1Register (Step 3
06, 304). As a result, the alternative station memory 11c is
Program network PI_AStations A that compose₁,
A₂Adjacent stations within the same program network with the same frequency
To be related and registered so that it can be understood that there is a relationship
(See FIG. 10 (2)).

Similarly, when the vehicle travels on the route a in FIG. 9 and sequentially passes through the broadcasting areas of the stations A ₂ and A ₃ which compose the same program network PI _A , the alternative station memory is used. 11c, as shown in FIG. 11 (1),
In the program network PI _A , frequencies f _A0 , f _A1 , f _A2 , and f _A3 of each receiving station are registered as receiving station frequencies, and each receiving station frequency is adjacent to the same program network PI _A. Station frequencies f _A1 , f _A0 ,
f _A2 , f _A1 , f _A3 and f _A2 are registered.

After that, the vehicle starts traveling on the route shown in FIG. 9b.
Station A₃While receiving the_A
PI different from_BYour program network
Station B ₀Tuning operation, the tuning control section 11d₀
Frequency f_B0Frequency control data corresponding to the PLL circuit
Output to 2 and station B₀(Step 10 in FIG. 4)
9). At this time, the vehicle is station B₀Enter the broadcasting area of
Assuming that there is a speaker B from station 7₀Broadcast
It In this state, the vehicle travels along the route shown in Fig. 9b.
Station B₀Same program outside the broadcasting area of
Network PI_BFrequency f_B1Station B₁Release of
Once in the transmission area, station B₀Received from
The alternate station search is performed based on the AF list, and the station B
₁To the reception state of the
Program network PI_BAbout the receiving station frequency f
_B0And f_B1Is registered and the receiving station frequency f_B0Against
F as the adjacent station frequency_B1Is registered, the receiving station frequency
f_B1F as the adjacent station frequency for_B0Is registered (Fig.
4 after step 105, see FIG. 11 (2)).

Further, the vehicle is station B.₁Out of the broadcasting area
Same program network PI _BThe frequencies that make up
f_B2Station B₂When entering the broadcast area, the tuning controller 11d
In the alternative station search by the
Program network PI_BReceiver frequency f at_B1
Station B₁Adjacent station frequency f to_B0(Fig. 7
Processing after step 402), station detection
Signal SD does not go to high level (N in step 406
O), and the receiving station frequency in the alternative station memory 11c.
f_B1Since no other adjacent station frequency for is registered
(YES in step 409, NO in step 410), station B₁Or
An alternative station search was performed based on the AF list received from
(Processing after step 105 in FIG. 4), station B₂Receipt of
State, and the program memory is stored in the alternative station memory 11c.
Network PI_BAbout the receiving station frequency f_B2Has additional registration
It is recorded and the reception station frequency f_B1Adjacent station to
F as wavenumber_B2Is registered, and the receiving station frequency f_B2Against
F as the adjacent station frequency_B1Is registered (step in FIG. 6
301, 305, 306, 304, see FIG. 12 (1)
See).

Here, assuming that the vehicle is in the broadcasting area of the station A ₂ , when the operation unit 12 selects the station A ₂ which forms the program network of PI _A , the tuning control unit 11d causes the station A to operate. _The frequency control data corresponding to the frequency f _A2 of 2 is output to the PLL circuit ₂ and tuned to the station A ₂ (step 109 in FIG. 4). Vehicle flows broadcast from the speaker 7 of the station A ₂ because it contains the broadcast area該局A _2.

[0038] In this state, the vehicle that has traveled in the path of c in FIG. 8, the frequency f _A5 constituting the same program network PI _A deviates from the broadcast area of the station A ₂ station A ₅
When the reception condition deteriorates, the tuning control unit 11d determines YES in step 103 of FIG. 4, and first, the program network PI is stored in the alternative station memory 12c.
It is checked whether the information about _A is registered (step 104), and since it is YES, it is then checked whether the frequency f _A2 of the currently received station A ₂ is registered as the receiving station frequency of the program network PI _A (FIG. 7). Step 401).

Since it is also YES here, the tuning controller 11d
From the alternative station memory 11c to the program network PI
Of _A, to tune to the first neighboring station frequency f _A1 for stations A ₂ of the frequency f _A2 which is being received (step 402-4
05). Then, it is checked whether the station detect signal SD input from the station detector 10 is high and a station is detected (step 406). Since the answer here is NO, the frequency f currently being received in the program network PI _A is stored in the alternative station memory 11c.
_A2 is tuned to the next adjacent station frequency f _A3 for station A ₂ (steps 409, 411, 403-405). Then, it is checked whether the station detect signal SD input from the station detector 10 is high and a station is detected (step 406).

Here again, the answer is NO, and the alternative station memory 11c
Program network PI registered in_AOf
Frequency f currently being received_A2To all neighbor frequencies for
Search has finished, and there is no station detected.
Because (YES in step 409, NO in 410), tuning
The control unit 11d is stored in the buffer memory 11a.
Station A₂Based on the AF list received from
(Step 105 and subsequent steps in FIG. 4). Station A_Five
At the time of switching to the station detect signal
SD becomes high level and the received electric field strength is constant
Since it is on the top, the tuning control unit 11d_FiveTo the receiving state of
Fixed (YES in step 204 of FIG. 5), alternative station information
The registration unit 11e stores the program in the alternative station memory 11c.
Network PI_AAbout the receiving station frequency f_A5Additional registration
While recording, the receiving station frequency f _A2Adjacent station frequency to
F as a number_A5Is registered, and the receiving station frequency f_A5Adjacent to
F as the station frequency_A2Is registered (step 30 in FIG. 6)
1, 305, 306, 304, see FIG. 12 (2)).

[0041] When Thereafter, the vehicle travels along the path of the d in Fig. 9, first, enter the broadcasting area off the broadcasting area station A ₂ stations A _5, the reception status of the station A ₅ worse Then, the tuning control unit 11d performs YE in step 103 of FIG.
If it is judged as S, it is checked whether or not the information about the program network PI _A is registered in the alternative station memory 12c (step 104). Since it is YES, the frequency f _A5 of the station A ₅ currently being received is registered as the receiving station frequency. It is checked whether or not (step 401 in FIG. 7).

Since the determination here is also YES, the tuning controller 11d
From the alternative station memory 11c to the program network PI
Of _A, to tune to the first neighboring station frequency f _A2 for station A ₅ frequency f _A5 currently being received (step 402-4
05). Then, it is checked whether the station detect signal SD input from the station detector 10 is high and a station is detected (step 406). Since the determination here is YES, subsequently, the received electric field strength signal is input from the signal meter 9 to temporarily store the received electric field strength, and it is checked whether the electric field strength is above a certain level (steps 407, 40).
8) Since the answer here is also YES, the frequency is fixed to the reception frequency f _A2 at that time, and the search for the alternative station ends. As a result, the same program that was previously received by the station A ₅ can be continuously received through the station A ₂ .

After that, when the vehicle leaves the broadcasting area of the station A ₂ and enters the broadcasting area of the station A ₃ and the reception condition deteriorates, the tuning control section 11d determines YES in step 103 of FIG. It is checked whether or not the information about the program network PI _A is registered in 12c (step 104), and since it is YES, it is checked whether or not the frequency f _A2 of the currently received station A ₂ is registered (step of FIG. 7). 401). Since the answer is YES, the tuning control unit 11d receives the frequency f currently being received in the program network PI _A from the alternative station memory 11c.
Tuning _A2 to the first adjacent station frequency f _A1 for station A ₂ (steps 402-405). Then, it is checked whether the station detect signal SD input from the station detector 10 is at a high level and a station is detected (step 406).

Since the answer here is NO, the alternative station
Program network PI in memory 11c_AOf the current
Frequency f currently being received_A2Station A₂Next adjacent station frequency to
Number f _A3(Steps 409, 411, 403)
~ 405). Then, from the station detector 10
The input station detect signal SD is high and the station
It is checked whether it has been detected (step 406).

Since the answer is YES this time, subsequently, the received electric field strength signal is input from the signal meter 9 to temporarily store the received electric field strength, and it is checked whether it is a certain value or more (steps 407 and 408). Therefore, the reception frequency f _A3 at that time is fixed and the search for the alternative station is completed. As a result, the same program that was previously received by the station A ₂ can be continuously received through the station A ₃ .

As described above, when the vehicle travels again on the route that has traveled while receiving the same program network in the past, it is registered in the alternative station memory 11c without using the AF list received from the receiving station up to that point. It is possible to quickly search for an alternative station without malfunction by using the same program network as the receiving station up to that point and using the frequency of the adjacent station that is adjacent to the receiving station up to that point. On the other hand, when using the AF list to search for an alternative station, it may be tuned to a station on another program network during the search, resulting in a problem that the search takes time or another program may be heard. To do. In this embodiment, the more the vehicle travels along various routes, the lower the frequency of occurrence of malfunctions.

[0047]

As described above, according to the present invention, initially, each time the current reception state of the receiving station deteriorates, the AF list included in the FM broadcast signal is referred to search for an alternative station of the same program network. , The frequency of the receiving station that has been receiving until then and the frequency of the alternative station after the search are related are registered in the memory so that it can be seen that they are in the adjacent station relationship in the same program network, and then a certain receiving station When the reception state of the A deteriorates, the station registered in the memory as a neighboring station in the same program network is preferentially searched for with respect to the certain reception station, and when the search is impossible, the AF included in the FM broadcast signal is detected. Referring to the list, search for an alternative station in the same program network, and the frequency of the receiving station that has been received until then and the alternative station frequency after the search is completed. When the receiving condition of a certain receiving station deteriorates, the certain receiving station is stored in the memory when the receiving state of the certain receiving station deteriorates because the two are registered in the memory so that they are related to each other in the same program network. On the other hand, a station registered as an adjacent station in the same program network is searched with priority, but the adjacent station is not a station that constitutes another program network. The frequency with which the set tunes to other program networks is significantly reduced temporarily, and in particular, when the vehicle travels the route that the vehicle has traveled in the past, it automatically follows the alternate station without causing any malfunction. Therefore, the broadcast will not be interrupted for a long time until the search is completed, and other programs will not be heard temporarily.

[Brief description of drawings]

FIG. 1 is an RD embodying an alternative station search method according to the present invention.
It is the whole S radio receiver lineblock diagram.

FIG. 2 is an explanatory diagram of data stored in an alternative station memory.

FIG. 3 is an explanatory diagram showing an example of an RDS data transmission format.

FIG. 4 is a first flowchart showing the operation of the controller.

FIG. 5 is a second flowchart showing the operation of the controller.

FIG. 6 is a third flowchart showing the operation of the controller.

FIG. 7 is a fourth flowchart showing the operation of the controller.

FIG. 8 is a fifth flowchart showing the operation of the controller.

FIG. 9 is an explanatory diagram showing a relationship between a traveling route of a vehicle and a broadcasting area of each broadcasting station.

FIG. 10 is an explanatory diagram of data stored in an alternative station memory.

FIG. 11 is an explanatory diagram of data stored in an alternative station memory.

FIG. 12 is an explanatory diagram of data stored in an alternative station memory.

FIG. 13 is an explanatory diagram of a conventional alternative station search method.

FIG. 14 is an explanatory diagram of another conventional alternative station search method.

[Explanation of symbols]

 3 Front End 4 Intermediate Frequency Amplification / Detection Circuit 8 RDS Decoder 9 Signal Meter 10 Station Detector 11 Controller 11c Alternate Station Memory 11d Tuning Controller 11e Alternate Station Information Register

Claims (1)

[Claims] 1. Initially, every time the current reception condition of the receiving station deteriorates, the AF list included in the FM broadcast signal is referred to search for an alternative station of the same program network, and the reception is performed until then. When the frequencies of the receiving station and the alternative station after the search are completed are related to each other so that it can be seen that they are adjacent to each other in the same program network, and then registered in the memory. , In a memory, a station registered as an adjacent station in the same program network with respect to a certain receiving station is preferentially searched, and when the search is impossible, the AF list included in the FM broadcast signal is referred to, While searching for an alternative station in the same program network, the frequency of the receiving station that has been received until then and the alternative station frequency after the search are completed are the same as each other. Alternative station search method that be registered in the memory, characterized by related as it can be seen that an adjacent station relation in beam network.