JP2008245076A - On-board broadcast receiving device and automatic presetting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to automatically select a broadcasting station suitable for viewing and to prevent a processing time from being extended unnecessarily. <P>SOLUTION: An on-board broadcast receiving device 1 includes a tuner circuit 3 which tunes to a reception frequency and outputs a reception signal, a detecting circuit 10 which outputs an S meter signal Sm indicating reception electric field intensity of the received signal received by the tuner circuit 3, and a control unit 20 which makes an available channel decision at the reception frequency that the tuner circuit 3 is receiving based upon the reception electric field intensity, and stores the reception frequency at which the presence of an available channel is decided in a preset memory 21. The control unit 20 decides whether current reception electric field intensity is equal to or larger than an available channel decision candidate threshold Eth1 each time the reception frequency of the tuner circuit 3 is varied by a predetermined step, and stores the current reception frequency as an available channel decision candidate to make an available channel decision only at the reception frequency stored as the available channel decision candidate when the current reception electric field intensity is equal to or larger than the available channel decision candidate threshold Eth1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a so-called auto-preset technique in which a frequency band used by a broadcast station is searched, a reception frequency capable of receiving a broadcast wave transmitted from the broadcast station is detected and automatically stored based on a received electric field strength.

Conventionally, an in-vehicle broadcast receiving device such as an in-vehicle radio device mounted on a vehicle searches a frequency band used for broadcasting, automatically stores a broadcasting station having a high received electric field strength, and One having a so-called auto-preset function assigned to a channel selection button is known. Thus, the user can listen to the broadcast of the broadcast station assigned to the channel selection button by pressing the channel selection button (see, for example, Patent Document 1).
JP 2002-314379 A

  By the way, the received electric field strength of the broadcast wave changes under the influence of the running state and location of the vehicle, the viewing time zone, the weather, the radio wave state, etc. It is not possible to accurately preset a broadcasting station suitable for viewing only by selection.

  Therefore, at the time of auto-preset, every time a reception frequency with a high received electric field strength is detected, a local determination is performed to determine whether the radio wave of the reception frequency is a broadcast wave transmitted from a broadcast station, Only those that are determined to be stationed are stored in the memory in the order of high received electric field strength or in the order of high / low reception frequency, and assigned to a predetermined channel selection button, so that only the broadcasting station suitable for viewing can be accurately Preset is possible.

However, in a place where there is a lot of noise, many reception frequencies at which the received electric field strength increases are detected. There is a problem that it becomes longer in proportion to.
The present invention has been made in view of the above-described circumstances, and can be used for in-vehicle broadcast reception that can automatically select a broadcasting station suitable for viewing and can prevent the processing time from being extended unnecessarily. It is an object of the present invention to provide an auto preset method suitable for use in an apparatus and this in-vehicle broadcast receiving apparatus.

  In order to achieve the above object, the present invention provides a tuner circuit that tunes to a reception frequency and outputs a received signal, a field strength detector that detects a received field strength of a received signal received by the tuner circuit, and A control unit that performs stationed determination at the reception frequency received by the tuner circuit based on the received electric field strength detected by the electric field strength detection unit, and stores the received frequency determined to be stationed in a preset memory. The control unit determines whether or not the received electric field strength detected by the electric field strength detection unit is equal to or greater than a localized determination candidate threshold every time the reception frequency of the tuner circuit is changed by a predetermined step. When the received electric field strength is equal to or greater than the stationed determination candidate threshold, the current received frequency is stored as a stationed determination candidate, and the received frequency stored as the stationed determination candidate is Providing vehicle broadcast receiver and performs determination seen the chromatic station.

  Further, the present invention provides the in-vehicle broadcast receiving apparatus according to the above invention, wherein the control unit receives the predetermined number of reception frequencies as the upper limit to a preset number of reception frequencies stored in the preset memory as the stationed determination candidate. The frequency is memorized.

  Further, the present invention provides the in-vehicle broadcast receiving apparatus according to the above invention, wherein the control unit stores the received electric field strength in association with each other when storing the received frequency as a stationed determination candidate, When the number of reception frequencies to be candidates exceeds the predetermined number, the reception frequencies are deleted in order from the lowest field strength signal among the stored reception frequencies of the station determination candidates. .

  Further, the present invention provides the in-vehicle broadcast receiving apparatus according to the above invention, wherein the control unit detects interference based on temporal fluctuations of the received electric field strength when the station determination is performed, and the interference is detected. A reception frequency that is not stored is stored in the preset memory.

  In order to achieve the above object, the present invention is an auto-preset method for searching for a predetermined frequency band and storing the reception frequency of the station in the preset memory, and each time the reception frequency is changed by a predetermined step, It is determined whether or not the received electric field strength is greater than or equal to a stationed determination candidate threshold, and when the received electric field strength is greater than or equal to the stationed determination candidate threshold, a first received frequency is stored as a stationed determination candidate And a second step of performing a stationed determination only on the reception frequency stored as the stationed determination candidate in the first step.

  According to the present invention, when a search is performed by changing the reception frequency by a predetermined step, a reception frequency whose received electric field strength is equal to or greater than the stationed determination candidate threshold is stored as a stationed determination candidate, and is stored as a stationed determination candidate. The presence determination is performed only for the received frequency. Therefore, since the reception frequency for performing the station determination is narrowed down as a station determination candidate in advance, the number of station determinations can be reduced. As a result, it is possible to prevent the processing time from being unnecessarily extended by narrowing down the stationed determination candidates in advance while automatically selecting a broadcasting station suitable for viewing by the stationed determination.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram illustrating a configuration of an in-vehicle broadcast receiving apparatus 1 according to the present embodiment.
In this figure, radio waves in a predetermined frequency band used for AM broadcasting are taken in via an antenna (ANT) 2, and a high frequency signal is output from the antenna 2 to a tuner circuit 3.
The tuner circuit 3 extracts a signal corresponding to the reception frequency from the high-frequency signal input from the antenna 2 and outputs the signal to the detection circuit 10 described later. The tuner circuit 3 includes a high-frequency amplifier (RF-Amp) 4 and a low-pass filter 5. A first frequency conversion circuit 6, a first intermediate frequency transformer (IFT) 7, a second frequency conversion circuit 8, a second intermediate frequency transformer (IFT) 9, and a detection circuit (DET) 10. Yes.

The high-frequency amplifier 4 amplifies the high-frequency signal output from the antenna 2, passes the low-pass filter 5, and outputs only the predetermined frequency band to the first frequency conversion circuit 6.
The first frequency conversion circuit 6 includes a first local oscillation circuit (OSC1) 11 that outputs a reference signal having a frequency instructed by a control unit 20 to be described later, a reference signal output from the first local oscillation circuit 11, and the high frequency signal. A first mixer (MIX1) 12 that mixes high-frequency signals output from the amplifier 4 and outputs an intermediate-frequency (IF) signal having a constant intermediate frequency (for example, 10.7 MHz) to the first intermediate-frequency transformer 7; is doing.

The first intermediate frequency transformer 7 functions as a filter that extracts the signal of the intermediate frequency component from the intermediate frequency signal output from the first frequency conversion circuit 6, and outputs the extracted intermediate frequency signal to the second frequency conversion circuit 8. .
The second frequency conversion circuit 8 converts the frequency of the intermediate frequency signal output from the first intermediate frequency transformer 7 into a predetermined frequency (for example, 450 kHz) and outputs the converted signal, and the second local oscillation circuit (OSC2) 13 The second mixer (MIX1) 14 that mixes the reference signal output from the second local oscillation circuit 13 and the intermediate frequency signal output from the first intermediate frequency transformer 7 and outputs the mixed signal to the second intermediate frequency transformer 12 (IFT). And have.

The second intermediate frequency transformer 12 functions as a filter in the same manner as the first intermediate frequency transformer 7, extracts an intermediate frequency signal of an intermediate frequency component from the intermediate frequency signal output from the second frequency conversion circuit 8, and detects a detection circuit ( DET) 10.
The detection circuit 10 envelope-detects an audio signal, which is a modulation signal, from the intermediate frequency signal output by the second intermediate frequency transformer 12 and outputs it to the low frequency amplifier circuit (Audio-Amp) 15.
The low-frequency amplifier circuit 15 amplifies the power of the audio signal and outputs it to the speakers 16 provided in the vehicle, and outputs audio from each speaker 16.
Further, the detection circuit 10 outputs the frequency of the detected intermediate frequency signal as an IF count value signal Sf to the control unit 20 via an A / D converter (not shown), and further indicates the received electric field strength. The signal is output to the control unit 20 through an A / D converter (not shown) as an S (signal) meter signal Sm.

  The control unit 20 centrally controls each unit of the in-vehicle broadcast receiving apparatus 1 and includes, for example, a microcomputer having various functions such as a program execution function and a data storage function. In particular, the control unit 20 automatically detects and stores a broadcast station, and when performing so-called auto-preset processing, the frequency of the reference signal output from the first local oscillation circuit 11 to the first frequency conversion circuit 6. The control signal Cs for changing the frequency is output, the reception frequency is changed at every predetermined step, and a predetermined frequency band is searched. The detected reception frequency of the broadcasting station at this time is a preset memory 21 provided in the control unit 20. Stored in

The auto preset process is performed when an auto preset instruction is input from the user via an operation unit (not shown), and a flowchart of the tote preset process is shown in FIG.
As shown in FIG. 2, when an auto-preset instruction is input (step S1), the control unit 20 sets a predetermined reception frequency band used for a predetermined broadcast such as AM broadcast or FM broadcast to the frequency band. A control signal Cs for setting the reception frequency to the lower limit frequency is output to the first frequency conversion circuit 6 in order to sequentially search for every predetermined step from the lower limit frequency (which may be the upper limit frequency) (step S2). ).

Next, the control unit 20 measures the received electric field strength at the current reception frequency based on the voltage of the S meter signal Sm (step S3), and determines whether or not the received electric field strength is equal to or greater than the stationed determination candidate threshold Eth1. Is determined (step S4).
This stationed determination candidate threshold Eth1 is a received electric field strength threshold for discriminating whether or not the current received frequency is the target of the stationed determination process, and is used for the stationed determination described later. The electric field strength is set slightly lower than Eth2.

When the received electric field strength at the current reception frequency is lower than the stationed determination candidate threshold Eth1 (step S4: No), the received frequency is excluded from the stationed determination candidates.
Then, the control unit 20 outputs a control signal Cs for increasing the frequency by one step to the first frequency conversion circuit 6 in order to receive the reception frequency of the next step (step S5), and the current reception frequency is If it does not exceed the upper limit frequency of the predetermined reception frequency band (step S6: No), the processing procedure is returned to step S3 in order to measure the reception electric field strength at the reception frequency.

On the other hand, in step S4, when the received electric field strength at the current reception frequency is equal to or greater than the stationed determination candidate threshold Eth1 (step S4: Yes), the received frequency is set as a candidate for stationed determination.
However, under a noisy reception state, there are many reception frequencies that exceed the station determination candidate threshold Eth1. Therefore, in this embodiment, the number of reception frequencies that are candidates for station determination is limited to a predetermined limit value (“12” in this embodiment), and the maximum number of reception frequencies that are determined to be stationed is a predetermined limit value. The following is set.

For this reason, the control unit 20 determines whether or not the number of memories stored as the reception frequency of the stationed determination candidate exceeds a predetermined limit value “12” (step S7), and if not (step S7: No), the received frequency and the received electric field strength (voltage value of the S meter signal Sm) are temporarily stored in a RAM memory (not shown) or the like (step S8), and the received frequency thus stored is received electric field strength. After sorting in descending order (voltage value of S meter signal Sm) (step S9), the processing procedure is shifted to step S5 in order to determine the candidate station for the reception frequency of the next step.
If the number of memories of the stationed determination candidate exceeds the predetermined limit value “12” (step S7: Yes), the control unit may leave the received frequency with a high received electric field strength as the stationed determination candidate. 20 deletes the lowest received electric field strength (voltage value of the S meter signal Sm) from among the received frequencies already stored in memory (step S10), and then moves the processing procedure to the above step S8. Memorize reception frequency.

  As a result of the above processing, in the predetermined frequency band used for broadcasting, the reception frequencies that are candidates for the station determination are extracted with the predetermined limit value (“12” in the present embodiment) as the upper limit. For this reason, even under reception conditions where there is a lot of noise and the reception field strength of each reception frequency is generally high, the maximum number of reception frequencies that are judged to be stationed does not exceed a predetermined limit value. The maximum time required for completion of auto-preset is restricted, and auto-preset is completed within a predetermined maximum time.

  Note that the predetermined limit value of the reception frequency that is a candidate for the station determination is set to be larger than the preset memory number (“6” in the present embodiment) of the broadcast station that is stored in the preset memory 21 as an auto preset. For example, it is set to twice the number of preset memories.

  Now, as described above, the control unit 20 limits the reception frequency, which is a candidate for station determination, to a predetermined limit value (in this embodiment, “12”) in a predetermined frequency band used for broadcasting. Is extracted, it is determined whether or not the number of memories of the reception frequency extracted as the stationed determination candidate is “0” (step S11). When the number of memories is “0” (step S11: Yes), the control unit 20 displays the contents of the preset memory stored in the preset memory 21 to indicate that a broadcasting station suitable for viewing has not been detected. The process is held as it is (step S12), and the auto-preset process is terminated (step S13).

  On the other hand, when the number of received frequency memories extracted as the stationed determination candidate is not “0” (step S11: No), the control unit 20 receives the received electric field strength for each received frequency stored as the stationed determination candidate. A control signal Cs for setting the reception frequency to the reception frequency with the highest received electric field strength is output to the first frequency conversion circuit 6 in order to perform the stationed determination in descending order (the voltage value of the S meter signal Sm) ( Next, step S14), and the presence determination is performed with respect to the reception frequency (step S15).

  In the presence determination in step S15, interference determination is also performed. More specifically, when interference occurs in a broadcast wave, although the received electric field strength is relatively large, it is difficult to view the broadcast due to the interference. Therefore, in the present embodiment, in order to prevent presetting of a broadcasting station in which such interference occurs, interference determination is also performed at the time of the station determination in step S15.

FIG. 3 is a flowchart of the station interference determination process.
As shown in this figure, the control unit 20 acquires the S meter signal Sm and the IF count value signal Sf in order to determine the station at the current reception frequency, and receives the received electric field strength and the intermediate frequency (IF) signal. The frequency (IF count) is measured (step S100).
Next, the control unit 20 performs a stationed determination based on whether the received electric field strength is equal to or greater than the stationed determination threshold Eth2 and the IF count value signal Sf is a predetermined value (step S101).

More specifically, the received electric field strength at the reception frequency becomes large when a broadcast wave is received. Therefore, a reception electric field strength that can be regarded as receiving a broadcast wave is set in advance in the above-described stationed determination threshold Eth2, and it is determined whether or not the current received electric field strength is equal to or greater than the above-described stationed determination threshold Eth2. Thus, it can be determined whether or not a broadcast wave is received. Further, the IF count value signal Sf becomes a predetermined value when the frequency of the intermediate frequency signal is a predetermined frequency, thereby determining whether or not the current reception frequency matches the transmission frequency of the broadcasting station. be able to.
That is, when the received electric field strength at the current reception frequency is equal to or higher than the received electric field strength that can be regarded as receiving a broadcast wave, and the current received frequency matches the transmission frequency of the broadcast station It can be determined that there is a broadcast wave at the current reception frequency.

  If the control unit 20 determines that there is no station at the current reception frequency as a result of the determination in step S101 (step S101: NG), it is not necessary to determine interference at this reception frequency. After the result is held in a RAM (not shown) or the like (step S107), the stationed interference determination process is terminated. On the other hand, when it is determined that there is a broadcast wave at the current reception frequency (step S101: OK), the control unit 20 performs the following process to detect interference at the reception frequency.

More specifically, when interference is occurring in the broadcast wave being received, the received electric field strength fluctuates with time, so that the fluctuation of the received electric field strength is detected based on the S meter signal Sm. It can be determined whether or not there is interference in the broadcast wave of the current reception frequency.
That is, the control unit 20 acquires the S meter signal Sm M times (M = 5 in the illustrated example) every predetermined time in order to detect temporal variation of the received electric field strength (step S102). And the control part 20 performs the following calculation in order to quantify the magnitude | size of the time fluctuation | variation of S meter by these S meter signals Sm.

That is, the control unit 20 calculates an average value (A) of S meter values based on the M S meter signals Sm (step S103).
For example, when the S meter signal Sm is acquired five times in step S102, the values of the respective S meters are S meter (1) = 31 dBu, S meter (2) = 34 dBu, S meter (3) = 36 dBu, When S meter (4) = 37 dBu and S meter (5) = 38 dBu, the average value (A) in step S6 is 35.2 dBu.

Next, the control unit 20 calculates the absolute value of the difference between the value of the M S meters and the average value (A), and calculates the average value (B) (step S104).
In the above example,
Average (B) = ((35.2-31) + (35.2-34) + (36-35.2)
+ (37-35.2) + (38-35.2)) / 5
= 2.16 dBu
It becomes. This average value (B) is a quantification of the time variation of the values of M S meters, that is, the possibility of interference, and the average value (B ) Also increases, and the probability of crosstalk increases.

  Then, the control unit 20 calculates a value obtained by subtracting a value obtained by multiplying the average value (B) by the coefficient N from the average value (A) of the M S meters (step S105), It is determined whether or not there is interference by comparing with the station determination threshold Eth2 used for the station determination in S101 (step S106).

More specifically, by subtracting the average value (B), which is a temporal variation component, from the average value (A) indicating the time average of the S meter, a correction value obtained by correcting the S meter value by the temporal variation component is obtained. Calculated. (The value of this coefficient N is determined according to how much the time-varying component is taken into account.)
As a result, as the temporal variation of the received electric field strength increases, that is, as the probability that interference occurs, the S meter correction value calculated in step S105 becomes smaller. Even when a certain average value (A) exceeds the station determination threshold Eth2 used for the station determination in step S101, the correction value of the S meter falls below a predetermined intensity and satisfies the condition of station determination. As a result, it is determined that there is interference in the interference determination in step S106.

  For example, in the above example, when the stationed threshold value Eth2 is set to 30 dBu, the measurement values of the five S meters all exceed the stationed threshold value Eth2, and it is determined that the station is judged to be stationed if determined only from the measured values of each time. The However, when the coefficient N = 3, the correction value of the S meter is 35.2-3 × 2.16 = 28.72 dBu, taking into account the time variation of the S meter, that is, the probability that interference occurs. Then, when the value of the S meter is corrected, the corrected value of the S meter is less than a predetermined intensity and falls below the localized determination threshold Eth2. As a result, it is possible to discriminate broadcasting stations where the reception electric field strength greatly varies with time due to interference and is highly likely to cause interference, and to prevent such broadcasting stations from being preset.

The control unit 20 stores the result of the interference determination in step S106 in, for example, a RAM (not shown) (step S107), and returns to the auto preset process in FIG.
If there is no broadcast station at the current reception frequency as a result of the presence / absence interference determination process, or if interference has occurred, the control unit 20 does not preset the reception frequency, and The following processing is performed to determine whether the reception frequency of the station determination candidate is stationed.

  That is, the control unit 20 determines whether or not the current received frequency has the lowest received electric field strength (voltage value of the S meter signal Sm) among the received frequencies stored as the stationed determination candidates ( Step S16) When a reception frequency having a reception electric field strength lower than the current reception frequency is stored (Step S16: No), the current reception is stored among the reception frequencies stored as stationed determination candidates. A control signal Cs for receiving a reception frequency having a reception electric field strength (voltage value of the S meter signal Sm) next to the frequency is output to the first frequency conversion circuit 6 (step S17). The processing procedure is returned to step S15 to perform station determination.

Also, as a result of the stationed interference determination process in step S15, if there is a broadcast station at the current reception frequency and no interference has occurred, the control unit 20 presets the reception frequency by a predetermined preset number. The following processing is performed in order to store in the memory 21 and perform presetting.
That is, the control unit 20 determines whether or not the preset number up to now exceeds a predetermined value “6” (step S18), and if not (step S18: No), the reception frequency and the received electric field The strength (voltage value of the S meter signal Sm) is stored in the preset memory 21 (step S19), and each of the reception frequencies preset in this way is given priority from the one having the highest received electric field strength (voltage value of the S meter signal Sm). In order to assign to a channel selection button (not shown), after sorting in the order of high received electric field strength (step S20), the processing in step S16 is performed to determine the candidate station for the reception frequency in the next step. Move procedure.

  If the preset number up to the present time exceeds the predetermined value “6” (step S18: Yes), the control unit 20 has already set the reception frequency with a high reception electric field strength to preferentially preset. After deleting the preset reception frequency having the lowest received electric field strength (voltage value of the S meter signal Sm) (step S21), the processing procedure is shifted to the above step S19 to preset the current reception frequency. To do.

  When the control unit 20 performs the stationed determination on all the reception frequencies stored as the stationed determination candidates (step S <b> 16: Yes), the current six receptions stored in the preset memory 21. The frequency is assigned to the channel selection button in order from the highest received electric field strength to perform presetting (step S22), and the control signal Cs for receiving the received frequency having the highest received electric field strength (voltage value of the S meter signal Sm). Is output to the first frequency conversion circuit 6 and set so as to receive a broadcasting station with the least noise and a good reception state (step S23), and then the auto-preset process is terminated (step S24).

  Thus, according to the present embodiment, every time the reception frequency is changed by a predetermined step in the auto-preset process, the reception frequency whose reception electric field strength is equal to or greater than the station determination candidate threshold is stored in advance as a station determination candidate, The reception frequency for performing the station determination is narrowed down, and the station determination is performed only for the reception frequency stored as the station determination candidate. As a result, the number of stationed determinations can be reduced, so that it is possible to automatically select a broadcasting station suitable for viewing by the stationed determination, and the processing time can be extended to zero by narrowing down the stationed determination candidates in advance. Can be prevented.

  In addition, according to the present embodiment, since the upper limit is set for the number of reception frequencies stored as the stationed determination candidate, the reception electric field strength at each reception frequency is increased due to, for example, a large amount of noise. However, since the number of stationed determination candidates is limited, the number of stationed determinations does not increase any more.

  Further, according to the present embodiment, when the number of reception frequencies that are the stationed determination candidates exceeds a predetermined upper limit number, the electric field strength signal is the highest among the reception frequencies of the stationed determination candidates that are already stored. Since it is configured to delete in order from the lowest, it is possible to leave a reception frequency with a high possibility of being stationed.

  In addition, according to the present embodiment, at the time of stationed determination, interference is detected based on temporal variation of the received electric field strength, and only the reception frequency where interference is not detected is stored in the preset memory 21. Even a broadcast wave of a broadcast station having a high received electric field intensity can exclude a broadcast station that is difficult to view due to interference and can preset only stations that are meaningful to the viewer.

  The above-described embodiment is merely an aspect of the present invention, and can be arbitrarily modified and applied within the scope of the present invention.

It is a block diagram which shows the structure of the vehicle-mounted broadcast receiver which concerns on embodiment of this invention. It is a flowchart of an auto preset process. It is a flowchart of a stationed interference determination process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 In-vehicle broadcast receiver 3 Tuner circuit 6 1st frequency converter circuit 10 Detection circuit 20 Control part 21 Preset memory Eth1 Stationed determination candidate threshold Eth2 Stationed determination threshold Cs Control signal Sf IF count value signal Sm S meter signal

Claims (5)

A tuner circuit that tunes to a reception frequency and outputs a reception signal;
An electric field strength detector for detecting the received electric field strength of the received signal received by the tuner circuit;
A control unit that performs stationed determination at the reception frequency received by the tuner circuit based on the received electric field strength detected by the electric field strength detecting means, and stores the received frequency determined to be stationed in a preset memory; Prepared,
The controller is
Each time the reception frequency of the tuner circuit is changed by a predetermined step, it is determined whether or not the reception electric field strength detected by the electric field strength detection unit is equal to or greater than a stationed determination candidate threshold, and the reception electric field strength is the presence or absence. When it is equal to or greater than a station determination candidate threshold, the current reception frequency is stored as a stationed determination candidate, and the stationed determination is performed only for the reception frequency stored as the stationed determination candidate. Broadcast receiving device. The in-vehicle broadcast receiving device according to claim 1,
The controller is
A vehicle-mounted broadcast receiving apparatus characterized by storing reception frequencies as the stationed determination candidates with an upper limit of a predetermined number larger than the preset number of reception frequencies stored in the preset memory. The in-vehicle broadcast receiver according to claim 2,
The controller is
When storing the received frequency as a stationed determination candidate, store the received electric field strength in association with each other,
When the number of reception frequencies to be the stationed determination candidates exceeds the predetermined number, the reception frequencies are deleted in order from the lowest field strength signal among the reception frequencies of the stored stationery determination candidates. An in-vehicle broadcast receiver characterized by the above. The in-vehicle broadcast receiving device according to any one of claims 1 to 3,
The controller is
An in-vehicle broadcast receiving apparatus characterized in that, when the stationed determination is made, interference is detected based on temporal variation of the received electric field strength, and a reception frequency in which the interference is not detected is stored in the preset memory. . An auto-preset method for searching a predetermined frequency band and storing the received frequency of the station in a preset memory,
Each time the reception frequency is changed by a predetermined step, it is determined whether or not the received electric field strength is greater than or equal to the stationed determination candidate threshold. If the received electric field strength is greater than or equal to the stationed determination candidate threshold, A first step of storing the frequency as a stationed determination candidate;
A second step of performing a stationed determination only on the reception frequency stored as the stationed determination candidate in the first step.

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