JP3115203B2 - Car radio receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to radio data multiplex broadcasting.
The present invention relates to an in-vehicle radio receiver capable of receiving data of a transmission system , particularly in a radio data multiplex broadcasting system .
The present invention relates to an in-vehicle radio receiver having an improved alternative frequency search function.

[0002]

2. Description of the Related Art Conventionally, RDS (Radio D
ata System) Radio receivers that can receive data have become widespread. Based on this RDS data, AF (Alternative
Frequency) search function can be executed, but this function is used when the car moves and goes out of the service area of the broadcasting station being listened to in the car radio receiver.
When the user enters the service area of another broadcasting station having a different frequency to the destination where the same broadcasting program is being broadcast, the system automatically switches to the receiving frequency of the another broadcasting station and continuously listens to the same broadcasting program. You can do it. Each broadcasting station transmits RDS data including, as an AF list, frequency data of a network station adjacent to the periphery of the service area of the broadcasting station.

[0003] Each broadcasting station also transmits a PI (Program Identification) code consisting of a country code and a broadcasting station code. The PI code is data represented by four hexadecimal digits. In the case of a network station, data of the same configuration is transmitted to each station. This PI code is used for discrimination so as not to receive the same frequency station different from the listening network station, and for PI search when it is not possible to move to the next broadcast station by AF search.

[0004] The AF search function generally operates as shown in the flowchart of FIG. First, the RDS key on the front panel of the receiver is operated to set the AF search execution mode. When a certain broadcast station, for example, the station A is received, the data of the AF list and the PI code sent from the station A are stored in the internal memory of the receiver. Is stored. During the reception of the station A, when it is detected that the vehicle has moved and deviated from the service area of the station A and the reception state has deteriorated (for example, the noise level in the received signal is equal to or higher than a predetermined level (for example, 1.5 V at IF output)). Is detected), the AF search is started,
The frequency data of the stations (for example, stations B, C, and D) in the AF list are swept in the order stored in the memory,
First, an N value corresponding to the frequency of the station B is output to the receiving circuit (step S31).

Next, the station corresponding to the N value, that is, B
The existence of the station is confirmed ( S32 ). This confirmation is made, for example, when the receiving station detects that the electric field strength as viewed from the S meter output is 20 dB.
μV or more and noise level at IF output is 1.5V
If the following reception conditions are satisfied, it is confirmed that "there is a station". If the reception conditions are not satisfied, it is determined that "there is no station".

[0006] In step S 32, if the presence of the B station is confirmed the process proceeds to step S33, and returns to the frequency of the original A station to be confirmed (S35). In step S33, it is checked whether the PI code of station B matches the code of station A currently being received. If the two PI codes do not match, the frequency is returned to the original station A frequency (S3
5). If the two PI codes match, the reception frequency is switched from station A to station B (S34), and reception at station B is continued. If the receiving station is not switched to the station B in the first AF search, the above-described AF search is sequentially performed for the next station in the AF list. In this way, even if the car moves and the reception condition of the broadcasting station that was initially listening deteriorates, the system automatically switches to the same broadcasting network station and continues to listen to the same broadcasting content in a good reception state. Can be.

[0007]

By the way, in the conventional AF search function, when the reception condition of the station currently listening is deteriorated, the station which satisfies the reception conditions and is in a state in which the PI code in the RDS data can be synchronized is obtained. Otherwise, it could not be received. For this reason, for example, in a place such as Germany where there is a broadcasting station with a lower modulation degree than other countries, even if there is a station with a low noise and a good reception state, it may not be able to be received by the AF search. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described conventional problem. Even when the PI code is not synchronized and the PI code is not determined during the AF search,
It is an object of the present invention to provide an on-vehicle radio receiver capable of switching a reception frequency to a station that is easier to listen to.

[0008]

SUMMARY OF THE INVENTION An on-vehicle radio receiver according to the present invention is a radio data multiplex broadcasting system transmitted from a currently receiving station and stored in an internal memory of the receiver.
Searching the alternative frequency list data in the data of the beam, the program identifies the field intensity matches the predetermined level or more and the station
In a vehicle-mounted radio receiver having an alternative frequency search function of switching a reception frequency to a station different from the currently receiving station having a different code, when the reception frequency is switched, the frequency data of the previous reception station is preferentially replaced for a certain period of time. a priority alternative frequency de <br/> over data storage processing means for storing in said memory as a frequency <br/> data, the reception frequency reception state of the station currently being received is deteriorated, corresponding to the alternative frequency list data if the not be switched, a priority alternative frequency data search means for searching the priority alternative frequency de <br/> over data,
Receiving frequency switching means for switching to a receiving frequency of a station corresponding to priority alternative frequency data whose electric field strength is equal to or higher than a predetermined level lower than the predetermined level.

Moreover, preferential alternative frequency data storage processing means, a storage processing means for storing in said memory the frequency data before the receiving station as the preferred alternative frequency data when switching the reception frequency, is stored in the memory the priority alternative frequency
Timer means for setting a storage duration of several data; and data erasing means for erasing priority alternative frequency data stored in the memory after a predetermined time has elapsed by the timer means.
Have

[0010]

The frequency data of a station that has experienced reception is stored as priority alternative frequency data for a certain period of time, and when the reception state of the currently receiving station deteriorates, a normal alternative frequency search is performed. If it is not possible to move to a different station, it is possible to search for priority alternative frequency data under reception conditions that are easier to receive than the alternative frequency search data, and switch to a broadcast station that has less noise than the currently receiving station to receive.

[0011]

FIG. 1 is a block diagram showing an embodiment of an on-vehicle radio receiver according to the present invention. In FIG. 1, 1 is an RF input terminal, 2 is a PLL receiving circuit, 3 is a muting circuit,
4 is a microcomputer (hereinafter referred to as a microcomputer), 5
Is an RDS data demodulation circuit, 6 is a reception sensitivity detection circuit, 7 is a memory, 8 is a frequency display, and 9 is a PS (Program Servic
e Name) display 10 is a key input circuit. The broadcast reception signal and RDS data of the broadcasting station are transmitted from RF input terminal 1 to P
When input to the LL receiving circuit 2, the microcomputer 4 uses the receiving sensitivity detecting circuit 6 to set the receiving conditions such that the received signal has an electric field strength of 20 dBμV or more as viewed from the S meter output and a noise level at the IF output of 1.5 V or less. When the detection signal that satisfies the condition is output, the muting circuit 3 is controlled to a non-operating state to output a demodulated audio signal. However, if the reception condition is not satisfied, no detection signal is generated from the reception sensitivity detection circuit 6, and the microcomputer 4 sets the muting circuit 3 to the operating state to cut off the audio signal. Further, the microcomputer 4 takes in the RDS data signal included in the received signal from the PLL receiving circuit 2 via the RDS data demodulating circuit 5 and stores the same in a memory 7 such as an SRAM. Frequency display 8 and PS display 9
Displays the receiving frequency and the name of the receiving broadcasting station under the control of the microcomputer 4 . The key input circuit 10 can selectively perform each function operation at the time of reception by a predetermined key operation.

In the above-configured on-vehicle radio receiver,
FIGS. 2 and 3 show the improvement of the AF search function of the present invention.
This will be described based on the flowchart shown in FIG. First, the RDS key of the key input circuit 10 is operated to set an AF search execution mode. When a certain broadcasting station, for example, station A is received, the AF list and PI code data sent from station A are stored in the memory 7 of the receiver. Is done. During the reception of the station A, when it is detected that the vehicle has moved and deviated from the service area of the station A and the reception state has deteriorated (for example, the noise level in the received signal is equal to or higher than a predetermined level (for example, 1.5 V at IF output)). ), The microcomputer 4 starts the AF search, and sweeps the frequency data of the stations (for example, stations B, C, and D) in the AF list in the order stored in the memory 7. First, an N value corresponding to the frequency of the station B is output to the PLL receiving circuit 2 ( S
1 ).

Next, the station corresponding to the N value, that is, B
The existence of the station is confirmed (S2). This confirmation is performed, for example, in the same manner as described above, based on the detection signal of the reception sensitivity detection circuit 6, when the electric field strength observed by the receiving station at the S meter output in the PLL receiving circuit 2 is 20 dBμV or more and the noise level at the IF output is If the reception condition of 1.5 V or less is satisfied, it is confirmed that "there is a station". If the reception condition is not satisfied, it is determined that "there is no station". Step S2
If the presence of the station B is confirmed, the process proceeds to step S3, and if not, the process proceeds to step S6.

In step S3, the PI code of station B is
A check is made to see if it matches the one currently received at station A. If the two PI codes do not match, the process proceeds to step S6. If the two PI codes match, the receiving frequency is switched from station A to station B (S
4) Reception of station B is continued. Next, when the receiving frequency is switched, the frequency data of the previous receiving station, that is, the station A, is stored in the memory 7 as priority AF data, and a timer inside the microcomputer 4 is set (S5). In other words, the AF data stored in the memory 7 is set as a priority AF data when a reception experience has been performed even once, and a flag is set to that effect. The timer runs for a fixed time (5-15 minutes, preferably 7 minutes).
Minute), and the frequency data of the station A is returned to the normal AF state after a predetermined time elapses by this timer, and the priority AF state is canceled.
It becomes F data. Steps S1 to S5 are executed each time the reception condition of the currently receiving station deteriorates, and the frequency data of the stations that have experienced reception are sequentially stored in the memory 7 as priority AF data for a certain period of time by the timer. You.

If the presence of a station is not confirmed in step S2, or if the PI codes do not match in step S3, it is confirmed in step S6 whether or not the AF search has been completed. In this case, the frequency returns to the original frequency of station A (S8). If the communication has been completed, the reception state of the currently receiving station, that is, the station A is confirmed (S7). If the electric field strength of the S-meter output is equal to or higher than a predetermined level (for example, 20 dBμV), the reception state is determined to be a good reception state, and the original frequency of the station A is returned in step S8. On the other hand, S
The electric field strength of the meter output is a predetermined level (for example, 20 dBμ).
If it is lower than V), the reception state is determined to be bad,
The priority AF search in step S9 is permitted.

The priority AF search operates according to the flowchart shown in FIG. That is, if it is determined in step S7 of FIG. 2 that the reception state is bad, the priority AF data stored in the memory 7 is searched (S21). When the presence of stations (for example, stations E and F) that have been received in the past and are sequentially stored as priority AF data is confirmed (S2).
2), the reception status of the E station stored at the head is confirmed. The confirmation at this time is performed under the reception conditions (for example, when the electric field strength as viewed from the S meter output is 15
Noise level of not less than dBμV and IF output is 1.
5 V or less). If the reception condition is good, the reception frequency is switched from the station A to the station E, and the reception at the station E is continued.

Note that the synchronization of the PI code of the station E is not confirmed. Because the frequency data of the station E has been received up to a certain period of time in the past (7 minutes in this embodiment) after confirming that the reception conditions and the PI code match in steps S2 and S3 in FIG. Since the frequency data is
This is because even if the I code is not synchronized, it is very likely that the station is broadcasting the same contents as the station currently being received. If it is determined in step S22 that there is no station, or if the reception state is determined to be poor in step S23, the frequency returns to the original station A (S25), and the remaining stations stored as priority AF data are processed. A priority AF search is performed. As described above, when the reception status of the broadcasting station that was initially listening to the car has deteriorated due to the movement of the car, first, the same broadcasting network station is automatically switched to the same broadcasting network station by a normal AF search, and the same broadcasting content is received in a good reception state. in it can continue to listen to, also, even if you did not be switched in the normal AF search, Roh than the station currently being received by the priority AF search
It is possible to move to a broadcasting station with little feeling of noise.

[0018]

According to the present invention, a currently noisy broadcasting station with a lot of noise is received, and an ordinary frequency is listed on the alternative frequency list.
Even when there are no other broadcast stations Utsureru alternative frequency search can more preferentially alternative frequencies <br/> search to noise impression less broadcasters. Also, according to the present invention, frequently,
It is necessary to move to the alternative frequency search, and it is possible to move even at a reception frequency where synchronization of the program identification code is difficult.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of an on-vehicle radio receiver according to the present invention.

FIG. 2 is a flowchart showing the operation of the on-vehicle radio receiver shown in FIG. 1;

FIG. 3 is a flowchart showing an operation of the on-vehicle radio receiver of FIG. 1;

FIG. 4 is a flowchart showing the operation of a conventional in-vehicle radio receiver.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 RF input terminal 2 PLL receiving circuit 3 Muting circuit 4 Microcomputer (priority alternative frequency data storage
Processing means, priority alternative frequency data search means, reception frequency
Also serves as number switching means. Timer means and data erasing means
Including steps. ) 5 RDS data demodulating circuit 6 receiving sensitivity detection circuit 7 memory 8 Frequency indicator 9 PS display 10 key input circuit

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

Claims (2)

(57) [Claims] 1. A radio data multiplex broadcast system transmitted from a currently receiving station and stored in an internal memory of a receiver.
Searches the alternative frequency list data in the data systems out,
A program whose electric field strength is equal to or higher than a predetermined level and matches the station.
An in-vehicle radio receiver having an identification code and having an alternative frequency search function of switching a reception frequency to a station different from the currently receiving station, wherein when the reception frequency is switched, the frequency data of the previous reception station is preferentially substituted for a predetermined time. frequency
A priority alternative frequency to be stored in the memory as numerical data; and a data storage processing means, when the reception state of the currently receiving station deteriorates and it is not possible to switch to the reception frequency corresponding to the alternative frequency list data. , the priority alternative frequency <br/> a priority alternative frequency data search means for searching the data, receiving frequency switching means for switching the reception frequency of the local electric field strength corresponding to the predetermined level lower than a certain level or higher priority alternative frequency data An in-vehicle radio receiver comprising: 2. A vehicle radio receiver according to claim 1, priority alternative frequency data storage processing means, switching priority alternative divides the frequency data before the receiving station when the reception frequency
Storage processing means for storing in the memory as wave number data, timer means for setting the storage duration of the priority alternative frequency data stored in the memory, and priority alternative stored in the memory after a predetermined time has elapsed by the timer means
Having a data erasing means for erasing the frequency data
An on- board radio receiver.