JPH057788Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to receivers, especially to the traffic information broadcasting system in West Germany, the USA ARI system, and the RDS
This invention relates to a receiver with a receiving sensitivity switching function suitable for seeking specific broadcasts such as traffic information in a broadcasting system.

[Conventional technology]

For example, in West Germany's traffic information broadcasting system,
One station selected for each region from each general broadcasting station is assigned as a traffic information broadcasting station (SK station).
Traffic information is broadcast at predetermined times.

The stations selected in this way transmit a special identification signal along with a normal broadcast signal, and by detecting the identification signal on the receiver side, various seek operations for SK stations are possible.

This identification signal includes an SK signal indicating that the station is a traffic information broadcasting station, a BK signal indicating the area, and a DK signal indicating that traffic information is being broadcast.

An example of a car radio conventionally used in this traffic information broadcasting system is shown in FIG.

Radio receiving section 12 connected to antenna 10
Then, a broadcast at an arbitrary frequency within a predetermined band is reproduced and output as a received audio signal.

At the antenna input stage of the radio receiving section 12,
LOCAL/DX switching circuit (attenuator circuit) 1
8, making it possible to switch the receiving sensitivity.

The reception frequency of this radio receiving section 12 is varied under the control of the microcomputer 14.

LOCAL/DX switching circuit 18 is determined by the user.
The reception sensitivity is switched between LOCAL and DX according to the operation of the LOCAL/DX switch 19.

For example, if you switch to the LOCAL side, even if you receive a broadcast with a strong electric field, the antenna input signal will be attenuated, so you can listen to it without distortion.

Conversely, when the setting is switched to the DX side, the attenuation is canceled and broadcasts with weak electric fields can be received.

Further, when the user operates the reception mode changeover switch 22 of the operation unit 16 to set the normal reception mode, for example, if the manual frequency variable up switch 26 or down switch 28 is operated, the operation of these switches will be performed. The microcomputer 14 performs up/down control of the receiving frequency on a step-by-step basis.

Based on frequency variable control by the microcomputer 14, the radio receiving section 12 increases or decreases the tuned frequency. When a broadcast signal is received, it is reproduced and output as a received audio signal.

This received audio signal is input to an audio section (not shown), where it is amplified and then output as audio from a speaker.

When the user who has listened to the broadcast determines that the content is of his/her preference and stops manual frequency variable operation, the microcomputer 14 stops variable control of the receiving frequency and continues receiving the desired station.

If the broadcast radio waves become weak and difficult to hear due to vehicle movement, if the user switches the LOCAL/DX switching circuit 18 to the DX side, the LOCAL/DX
The switching circuit 18 is switched to the DX side.

This removes the attenuation from the antenna input, increasing reception sensitivity and making it possible to listen to even weak field broadcasts.

Separately, if the user wishes to tune the receiver to a traffic information broadcasting station, the user operates the reception mode changeover switch 22 of the operation unit 16 to set the SK reception mode.

Then, the microcomputer 14 executes a seek (SEEK) process for the SK station. That is, the receiving frequency is increased one step at a time from the previous receiving frequency.

In response to this up control, the radio receiving section 12 increases the tuning frequency one step at a time, and the identification signal detection circuit 24 connected to the intermediate frequency output stage of the radio receiving section 12 detects the SK signal from the traffic information broadcasting station. (Actually, BK and DK signals are also detected at the same time.)

The output of the identification signal detection circuit 24 is monitored by the microcomputer 14, and as long as no SK signal is detected, it continues to increase the reception frequency. When the receiving frequency reaches the upper limit of the band, up control is performed after moving to the lower limit of the band.

Thereafter, with variable control of the receiving frequency, when the tuned frequency in the radio receiving section 12 matches the SK station and the SK signal is detected in the identification signal detection circuit 24,
A detection signal is output to the microcomputer 14.

The microcomputer 14 is energized by the SK signal detection signal input, stops variable control of the receiving frequency, and fixes the tuning frequency of the radio receiving section 12.

As a result, if the SK station related to the tuned frequency is currently broadcasting traffic information, you can immediately listen to the content from the speaker, and even if the SK station related to the tuned frequency is not currently broadcasting traffic information, when it is broadcast at a predetermined time later, the content can be heard from the speaker. You can listen to traffic information broadcasts more easily.

[Problem that the invention attempts to solve]

However, in the conventional technology described above, if the user has switched the reception sensitivity to the LOCAL side in advance,
Even if you set the SK reception mode and try to seek an SK station, if there is only an SK station with a weak electric field strength at the vehicle's current position, the identification signal detection circuit 24 will not detect the identification signal even if the frequency of the SK station and the reception frequency match. There was a problem that the SK could not be detected, and as a result, it became impossible to seek the SK, making it impossible to listen to the necessary traffic information.

In view of the problems of the prior art, the present invention aims to provide a receiver that can reliably catch a specific station even if the user seeks for the specific station with the receiving sensitivity set low. , its purpose.

[Means for solving the problem]

The receiver according to this invention includes a receiving means for receiving a predetermined band according to variable control of the receiving frequency, a receiving sensitivity switching operating means for switching the receiving sensitivity of the receiving means, and a receiving sensitivity switching operating means for switching the receiving sensitivity of the receiving means. Receiving sensitivity switching means for switching the receiving sensitivity of the receiving means to high or low according to an operation or a predetermined control input; identification signal detection means for detecting a predetermined identification signal transmitted from a specific station; and a seeker for instructing to seek a specific station. Instruction operation means: When a seek is instructed by the seek instruction operation means, the reception sensitivity is left as before and the reception frequency is controlled to be variable for the reception means while monitoring the detection output of the identification signal detection means. , a first seek control means for seeking a specific station by stopping variable control of the receiving frequency when an identification signal is detected; 1. When a seek is performed under the control of the seek control means and no identification signal transmitting station is found within the band, the receiving sensitivity switching means is controlled to switch to the high sensitivity side, and then the identification signal detection means is switched again. a second seek control means for performing variable control of the receiving frequency on the receiving means while monitoring the detection output, and for seeking a specific station by stopping the variable control of the receiving frequency when the identification signal is detected; It is characterized by

〔Example〕

One embodiment of this invention will be described with reference to FIG.

FIG. 1 shows a block diagram of a car radio for a West German traffic information broadcasting system according to this invention.

A radio receiving unit 12 is connected to the output side of the antenna 10, and among the received signals caught by the antenna 10, the received signal related to the tuning frequency set by the radio receiving unit 12 is reproduced, and the received audio signal is reproduced. is output as

At the antenna input stage of the radio receiving section 12,
LOCAL/DX switching circuit (attenuator circuit) 1
8, making it possible to switch the receiving sensitivity.

For example, if you switch to the LOCAL side, even if you receive a broadcast with a strong electric field, the antenna input signal will be attenuated, so you can listen to it without distortion.

Conversely, when the setting is switched to the DX side, the attenuation is canceled and broadcasts with weak electric fields can be received.

The reception frequency of this radio receiving section 12 is varied under the control of the microcomputer 14A.

The receiving sensitivity of the LOCAL/DX switching circuit 18 is also switched under the control of the microcomputer 14A.

An identification signal detection circuit 24 is connected to the intermediate frequency signal output stage of the radio receiving section 12, and the received signal includes an identification signal (SK signal, BK signal, DK signal) for identifying the traffic information broadcasting station. This is detected and a detection signal is output.

The received audio signal from the radio receiving section 12 is amplified by an audio section (not shown) and then outputted as audio from a speaker.

Radio receiving section 12, LOCAL/DX switching circuit 1
8. A microcomputer 14A is connected to the identification signal detection circuit 24, and is configured to receive predetermined control.

Further, an operating section 16A is connected to the input side of the microcomputer 14A. This operation section 1
6 includes a LOCAL/DX switch 20, a reception mode switch 22 for switching between normal reception mode and traffic information broadcast reception mode (SK reception mode), an up switch 26 for the user to manually turn up and down the reception frequency, A down switch 28 and the like are provided, and various switch signals according to the user's switch operations are output to the microcomputer 14A.

In addition, a display unit 30 is connected to the output side of the microcomputer 14A, and the sensitivity display, SK
Detection display, BK display (area display), etc. are performed.

The microcomputer 14A includes a CPU,
Consists of ROM and RAM connected via a bus, and performs normal reception control, SK seek control, LOCAL/DX switching control, display control processing, etc. according to the user's switch operation according to a predetermined program stored in the ROM. .

Specifically, when the user operates the LOCAL/DX switch 20 or when the need arises during SK seek, the sensitivity mode switching control for the LOCAL/DX switching circuit 18 is performed, and the display unit 3
Performs sensitivity mode display control for 0.

In response to this switching control, the LOCAL/DX switching circuit 18 attenuates or cancels the attenuation on the antenna input, thereby switching the receiving sensitivity from high to low.

Further, under the sensitivity mode display control, the display unit 30 displays the sensitivity mode of <LOCAL> or <DX>.

When the user operates the up switch 26 or the down switch 28 in the normal reception mode, the microcomputer 14A performs up control or down control of the reception frequency of the radio reception section 12.

In addition, when set to SK reception mode, variable control of the reception frequency for the radio reception unit 12, monitoring of input from the identification signal detection circuit 24, fixed control of the reception frequency when detecting the SK signal, SK detection display control, and BK Display control, when it is not possible to seek in LOCAL mode within a specified band
Re-seek control after automatically switching to DX mode,
Controls switching to normal reception mode when seek ultimately fails.

The radio receiving section 12 is connected to the microcomputer 1
The tuning frequency is raised or lowered under 4A frequency variable control.

The display section 30 receives <SK> under SK detection display control.
Characters are displayed, and area display is performed under BK display control.

Next, the operation of the above embodiment will be explained with reference to the flowcharts of FIGS. 2 and 3.

When the user turns on the power switch (not shown), the microcomputer 14A performs a predetermined initial setting process, sets the reception mode to the normal reception mode, sets the sensitivity mode to the LOCAL mode, and sets the power switch to the previous power switch. Reception control is performed using the reception frequency immediately before the signal is turned off (step 40).

Under this reception control, the radio receiving section 12 receives the broadcast that was last listened to last time, and outputs the reproduced received audio signal.

In LOCAL mode, microcomputer 14
A performs LOCAL side switching control for the LOCAL/DX switching circuit 18.

Therefore, the antenna input is attenuated, and even strong electric field broadcasts can be received without distortion.

In addition, microcomputer 1 in LOCAL mode
4A controls the display unit 30 to display the LOCAL mode, and sets the sensitivity mode display to <LOCAL>.

The received audio signal output from the radio receiving section 12 is amplified by the audio section and then output as audio from the speaker.

After the initial setting process, the microcomputer 14A
checks the switch signal input from the operation unit 16A, and determines whether the reception mode changeover switch 22 is operated, whether the LOCAL/DX changeover switch 20 is operated, the frequency up switch 26,
It is repeatedly determined whether or not the down switch 28 has been operated (steps 42, 44, and 46).

Here, when the user presses the up switch 26 to change the reception frequency, an up switch on signal is output from the operating section 16A to the microcomputer 14A while the user presses the up switch 26.

The microcomputer 14A is energized by this up/down switch signal input and determines YES in determining whether or not the up/down operation has been performed.
Step-up control of the reception frequency is performed (step 48).

As a result, the tuning frequency of the radio receiving section 12 increases by one step.

Next, the microcomputer 14A checks the signal input from the operation section 16A, and determines whether or not the up-switch ON signal is still being input, that is, whether or not the user continues to press the up-switch. 50), if it continues, the process returns to step 48 and step-up control of the receiving frequency is performed again.

This further increases the tuning frequency by one step.

Thereafter, in the same manner, while the user continues to operate the microcomputer 14A.
repeats the YES determination in step 50 and the step-up control of the receiving frequency in step 48.

As a result, the tuning frequency at the radio receiving section 12 changes continuously one step at a time, and when a new broadcasting station is caught, the received audio signal is reproduced and output. Then, it is amplified by the audio section and output as audio from the speaker.

When the user listens to this broadcast and determines that the broadcast content is of his/her preference, the user releases the up switch 26 and stops outputting the up switch on signal from the operating section 16A.

Then, the microcomputer 14A makes a negative determination in step 50, and in this case stops variable control of the receiving frequency and fixes the tuned frequency of the radio receiving section 12 to the frequency of the desired station (step 52).

As a result, the broadcast output of the desired station is maintained from the speaker.

After the processing in step 52, the microcomputer 14A returns to step 42 and again checks whether there is a reception mode switching operation, whether there is a sensitivity switching operation, and whether there is an up/down switch operation.
Repeats determination of whether or not there is a down operation.

If the user is far from the desired station and the received field strength is weak and the received audio cannot be heard clearly, the user should set the LOCAL/DX selector switch 20 on the operation panel 16A to 1.
Just press it twice.

Then, a LOCAL/DX changeover switch-on signal is output from the operating section 16A.

The microcomputer 14A is energized by this signal input and first judges YES at step 44,
After confirming that it was in LOCAL mode (step 54), LOCAL/DX switching circuit 18
DX side switching control is performed for (step 56).

As a result, the antenna input is no longer attenuated, and the broadcast can be reliably heard.

Further, the microcomputer 14A controls the display unit 30 to display the DX mode, and sets the sensitivity mode display to <DX> (step 58).

After that, if the vehicle moves closer to the broadcast station and the received electric field becomes stronger, making it easier to hear the received broadcast,
Press the LOCAL/DX switch 20 once again to return to the original LOCAL mode (step
44, 54, 60, 62).

In this state, the user then wishes to listen to traffic information broadcasting and turns the reception mode switch 22 to 1.
When the button is pressed twice, a receive mode switching switch signal is sent from the operating section 16A to the microcomputer 14A.
Output to.

The microcomputer 14A is energized by this reception mode changeover switch-on signal input and starts the step.
42 is judged as YES. Then, proceed to step 64 in Fig. 3, and after setting the SK reception mode,
Clear N and K (step 66).

Then, the reception frequency at that point is stored as _p (step 68).

Next, the switch signal input from the operating section 16A is checked to determine whether or not the user has performed a receiving sensitivity switching operation (step 70).

If the user does not specifically switch to the DX mode, the microcomputer 14A determines NO in step 70 and then switches the identification signal detection circuit 2 to the DX mode.
The input from 4 is checked to determine whether or not the SK signal has been detected (step 72).

The identification signal detection circuit 24 detects the presence or absence of an SK signal in the received signal, and if there is a nearby SK station related to frequency _p and an SK signal is detected,
Outputs the SK signal detection signal (at this time,
BK signal is also output).

Conversely, if there is no SK station related to frequency _p , no SK signal detection signal is output.

If no SK signal has been detected yet, step-up control of the receiving frequency is performed to raise the tuning frequency of the radio receiving section 12 by one step (step 74).

Then, check that the same sensitivity mode has not returned to the original _p (that is, the entire receiving band has not been sought once while in the same sensitivity mode), and the receiving frequency has not exceeded the upper limit frequency of the receiving band. After checking (steps 76 and 78), step 70
After returning to step 72 and confirming that no receiving sensitivity switching operation has been performed, it is again determined whether an SK signal has been detected (step 72).

If no SK signal is detected yet, step-up control of the reception frequency is performed again, and radio reception section 1
2's tuning frequency is increased by one step (step 74).

After confirming that it has not returned to the original _p while still in the same sensitivity mode and that the receiving frequency has not exceeded the upper limit frequency of the receiving band (steps 76 and 78), the process returns to step 70.

From now on, repeat the same process,
LOCAL/DX selector switch 20 cannot be operated
When the receiving frequency exceeds _e by the step-up control in step 74 while the LOCAL mode remains in place and no SK signal is detected, the microcomputer 14A determines YES in step 78.

In this case, the microcomputer 14A performs reception control at the lower limit frequency _s of the reception band, and tunes the radio reception section 12 to the frequency _s (step 1).
80).

Then, each process of steps 70, 72, 74, 76, and 78 is repeated again. Under the control in step 74, before the tuning frequency reaches the original _p , the tuning frequency is
Matches the frequency of the SK station, and the identification signal detection circuit 24
When detects the SK signal, it immediately outputs the SK signal detection signal to the microcomputer 14A (at this time, the BK signal is also output to the microcomputer 14A).
output to A).

The microcomputer 14A is energized by the input of the SK signal detection signal and makes a YES judgment in step 72.
Then, variable control of the reception frequency is stopped (step 82).

As a result, the tuning frequency of the radio receiving section 12 is
It is fixed to the frequency of the SK station, and the broadcast content of the SK station is output as audio from the speaker.

At this time, if the SK station is already broadcasting traffic information, the user can immediately listen to the desired traffic information.

Moreover, the broadcasting station you were listening to before switching the reception mode and the station detected by this seek are usually located close to each other, such as in the center of a city, and as a result, the received electric field strength is strong. Although there are many areas where the signal is slow, the reception sensitivity is set to LOCAL, so you can listen to traffic information broadcasts without distortion.

If this SK station is on a regular broadcast program, you will still not be able to listen to traffic information.

Thereafter, when the time comes for the SK station to implement the traffic information broadcast program, the user can listen to the desired traffic information.

After the process in step 82, the microcomputer 14A controls the display unit 30 to perform SK detection display control.
Performs BK display control to display the characters <SK> and area information indicated by the BK signal (step
84).

Thereafter, the microcomputer 14A checks the signal sent from the operation section 16A, and the user selects the reception mode changeover switch 22 and LOCAL/
It is repeatedly determined whether or not the DX selector switch 20 has been operated (steps 86 and 88), and the user selects the receive mode selector switch 22 and LOCAL/
If neither of the DX changeover switches 20 is operated, broadcast reception of the previously sought SK station will continue.

After that, when the user who has already heard the necessary traffic information presses the reception mode switch 22 once to return the radio to the normal reception mode, the operation section 16A
A reception mode switching switch-on signal is output from the terminal.

When the microcomputer 14A inputs this receive mode changeover switch-on signal, the process proceeds to step 86.
If the answer is YES, proceed to step 90, switch to normal reception mode, and then proceed to step 42 in Figure 2.
Return to

If after starting the SK seek, if the traffic information broadcasting station is not found and the receiving band is circled once, the microcomputer 14A returns YES in step 76.
At this time, the process proceeds to step 92, where it is determined whether the sensitivity mode up to that point was the DX mode.

In this case, it is already set to LOCAL mode, so the answer is NO.

That is, the antenna input is attenuated, and even if there is an SK station that can be received in the receiving band, it is far away and its electric field strength is weak, so there is a possibility that the SK signal cannot be detected.

Therefore, the microcomputer 14A is
The LOCAL/DX switching circuit 18 is controlled to switch to the DX side (step 94). This results in
The LOCAL/DX switching circuit 18 releases the attenuation of the antenna input.

This makes it possible to receive even SK stations with weak electric field strength.

Next, the microcomputer 14A controls the display unit 30 to display the DX mode, sets the sensitivity display to <DX> (step 96), and then sets K to 1.
(Step 98).

And the microcomputer 14A is a step
Return to 78.

After determining NO in this step 78, the processing in steps 70 to 78 is repeated again.

As a result, SK seek will now be executed under DX mode.

After that, without the user changing the sensitivity,
If an SK signal related to an SK station with a weak electric field strength is detected at a certain receiving frequency while the receiving frequency changes within the ranges _p to _e and _s to _p , the microcomputer 14A determines YES in step 72. Then, the reception status of the SK station is fixed (steps 82 and 84).

This allows you to listen to traffic information that was impossible to hear in LOCAL mode.

If you automatically switch to DX mode, _p ~ _e , _s ~ _p
When the microcomputer 14A cannot find an SK station even after seeking the frequency range p, the microcomputer 14A returns YES in step 76 when the receiving frequency reaches _p .
It is determined that this is the case, and the process moves to step 92.

Since we were in DX mode this time, we proceed to step 100 and determine whether K is 1 or not.

In this case, since K=1, it is judged as YES.

That is, since there is no SK station with strong electric field strength or weak electric field strength within the reception band, the microcomputer 14A stops variable control of the reception frequency and stops SK seek (step 102).
After switching to normal reception mode with the reception frequency set to _p (step 104), proceed to step 42 in Figure 2.
Return to

Unlike this, in advance in normal reception mode,
When the user is driving in the suburbs and has switched the reception sensitivity to DX mode and operates the reception mode changeover switch 22 to set the SK reception mode, the SK seek process by the microcomputer 14A is performed as follows. Ru.

First, after clearing N and K (step 66),
The received frequency up to that point is stored as f _p (step 68).

If the user does not perform a sensitivity switching operation, the reception frequency is increased from f _p until the SK signal is detected (steps 70 to 78).

When the receiving frequency reaches _e , it moves to _s (YES in step 78, 80), and then increases the receiving frequency while searching for an SK station again (step 70).
~78).

If the SK signal is detected on the way, the microcomputer 14A determines YES in step 72,
Fix to the reception state of the SK station (steps 82, 84).

This allows you to listen to traffic information broadcast from SK stations. Moreover, when the vehicle is driving in the suburbs and is receiving normal reception in DX mode, the traffic information broadcasting station is often far away from the vehicle's location, so if it is in DX mode under normal reception mode, , SK seek is performed directly in DX mode, so it is possible to quickly catch an SK station with a weak electric field and quickly finish the seek operation, which prevents the user from feeling discomfort due to repeated intermittent reception during seek. You don't have to do it.

Even if the receiving frequency is varied up to the original _p , SK
When no signal is detected, the microcomputer 14A detects the signal when the receiving frequency reaches _p .
If YES is determined in step 76, step 92
, and determine whether it was in DX mode up to that point.

In this case, the answer is YES, so the microcomputer 14A then judges whether K=1 or not (step 100). Since the answer is NO here, N is incremented to N=1 (step 106), and then it is judged whether N is 2 or not (step 108).

Since the SK seek of the receiving band in DX mode has only been performed once, the microcomputer 14A judges NO at step 108 and proceeds to the next step.
Return to 78.

Then, after determining NO in step 78, the processing in steps 70 to 78 is repeated again.

This will cause the SK seek to be executed again under DX mode.

After that, without the user changing the sensitivity,
While the receiving frequency changes in the ranges _p to _e and _s to _p , the SK station with a weak field strength at a certain receiving frequency
If an SK signal is detected, the microcomputer 14A determines YES at step 72, and fixes the receiving state to the SK station (steps 82, 84).

This allows you to listen to traffic information broadcast from SK stations.

If the SK station broadcast is exposed to a strong electric field due to vehicle movement, etc., if the user presses the LOCAL/DX switch 20, the LOCAL/DX
A DX changeover switch on signal is output, and the microcomputer 14A is energized by this signal input.
, it is judged as YES in step 88.

At this time, the microcomputer 14A confirms that the DX mode has been set (step 110), then controls the LOCAL/DX switching circuit 18 to switch to the LOCAL side, attenuates the antenna input, and outputs the audio. In addition to eliminating distortion of the output, LOCAL mode display control is performed on the display section 30 to set the sensitivity display to <LOCAL> (step 112).

Thereafter, when the user who has heard the necessary traffic information performs a reception mode switching operation, the mode is switched to the normal reception mode (steps 86 and 90).

If the SK station cannot be detected even after seeking the reception band again in the preset DX mode, when the reception frequency becomes _p again, the microcomputer 14A proceeds to step 76.
Decide YES.

At this time, the process moves to step 92, and it is determined whether or not the DX mode has been in use until then.

In this case, the answer is YES, so the microcomputer 14A next confirms that K is not 1 (step 100), and increments N.
=2 (step 106). Then, it is determined whether N is 2 (step 108).

The microcomputer 14 has already performed the SK seek of the reception band in DX mode twice.
Since A determines YES in step 108 and there is no SK station within the receiving band even if the electric field strength is weak, the microcomputer 14A stops variable control of the receiving frequency and stops SK seek (step 102). ), after switching to the normal reception mode with the reception frequency set to _p (step 104), the process returns to step 42 in FIG.

Note that when the SK reception mode is set with the normal reception mode switched to LOCAL mode in advance, when the user presses the LOCAL/DX switch 20 to increase reception sensitivity during SK seek, the microcomputer 14A is step
If the result is 70, it is judged as YES and the process moves to step 114.

After confirming that the mode has been in LOCAL mode up to that point, the LOCAL/DX switching circuit 18 is controlled to switch to the DX side to release attenuation (step 116), and the display unit 30 is controlled to display the DX mode. to display the sensitivity <DX>
(Step 118).

Then, clear N and K (step 120), _p
After changing to the reception frequency at that time (step 122), the process advances to step 72.

Thereafter, the reception frequency is increased in DX mode until an SK station is detected (steps 70 to 78).

When the receiving frequency reaches _e , move to _s and increase the frequency (YES in step 78, 80, 70~
78).

If an SK station is detected while seeking from _p (changed value) to _e and from _s to _p , the receiving frequency is fixed (steps 72, 82, 84).

Conversely, when the receiving frequency reaches _p , which was changed in step 122, without any SK station being detected in DX mode, the microcomputer 14A
After determining YES at 76, move to step 92.

After confirming that it is in DX mode up to that point, it is determined whether K is 1 or not (step 100). Since it is NO in this case, the process proceeds to step 106 and after incrementing N, it is determined whether N = 2 or not (step 100). 108).

Since the seek has only been performed once after changing to the DX mode, and N=1, the microcomputer 14A judges it as NO and returns to step 78 to try again.
Perform SK seek in DX mode.

If the SK station cannot be detected even after seeking again, the mode is switched to the normal reception mode when the reception frequency reaches the changed _p again (steps 76 and 92 determine YES, step 100 determines NO, step 106 ，
108, YES judgment, 102, 104).

Also, during SK seek after the SK reception mode has been set in the state where the normal reception mode has been switched to the DX mode, or in the LOCAL mode.
No SK station could be detected even after multiple seeks, and step 94.
When the user presses the LOCAL/DX switch 20 to switch the reception sensitivity during SK seek after the automatic switching to DX mode by the processing in step 96, the microcomputer 14A switches to the DX mode.
If the result is 70, it is judged as YES and the process moves to step 114.

After confirming that it was in DX mode up to that point, switch to LOCAL/DX switching circuit 18.
Switching control is performed to the LOCAL side to apply attenuation (step 124), and LOCAL mode display control is performed on the display section 30 to set the sensitivity display to <LOCAL> (step 126).

Then proceed to step 120 and clear N and K.
After changing _p to the reception frequency at that time (step 122), the process advances to step 72.

Thereafter, the receiving frequency is increased in LOCAL mode until an SK station is detected (steps 70 to 78).

When the receiving frequency reaches _e , move to _s and increase the frequency (YES in step 78, 80, 70~
78).

If an SK station is detected while seeking from _p (changed value) to _e and from _s to _p , the receiving frequency is fixed (steps 72, 82, 84).

Conversely, when the receiving frequency reaches _p , which was changed in step 122, without any SK station being detected in the LOCAL mode, the microcomputer 14A determines YES in step 76, and then proceeds to step 92.

Then, after confirming that it is in LOCAL mode, the LOCAL/DX switching circuit 18 is
Perform switching control to the DX side (step 94).

As a result, the LOCAL/DX switching circuit 18 releases the attenuation of the antenna input.

This makes it possible to receive even SK stations with weak electric field strength.

Next, the microcomputer 14A controls the display unit 30 to display the DX mode, sets the sensitivity display to <DX> (step 96), and then sets K to 1.
(Step 98) and return to Step 78.

Then repeat steps 70 to 78 again.
This time, execute SK seek under DX mode.

After that, without the user changing the sensitivity,
If an SK signal related to an SK station with a weak electric field strength is detected at a certain receiving frequency while the receiving frequency changes within the ranges _p to _e and _s to _p , the microcomputer 14A determines YES in step 72. Then, the reception status of the SK station is fixed (steps 82 and 84).

This allows you to listen to traffic information that was impossible to hear in LOCAL mode.

If you automatically switch to DX mode, _p ~ _e , _s ~ _p
When the microcomputer 14A does not find an SK station even after seeking in the frequency range p, the microcomputer 14A switches to the normal reception mode when the reception frequency reaches _p (determined YES in steps 76, 92, and 100, 102,
104).

According to this embodiment, if the user does not want distortion in the audio output due to strong electric field SK stations and switches the reception sensitivity to LOCAL mode, SK seek is performed in LOCAL mode regardless of before or after the start of SK seek. Therefore, there is no distortion in the audio output when an SK station is detected. If under LOCAL mode
If the SK station cannot be detected even after performing SK seek, the microcomputer 14A
Switching control is performed on the DX switching circuit 18 to automatically switch the sensitivity to DX mode and perform SK seek again, so it is possible to capture stations where the electric field strength was too weak to be detected in LOCAL mode at the vehicle position. Therefore, necessary traffic information can be reliably heard.

In addition, when the vehicle is driving in the suburbs and is performing normal reception in DX mode, when SK seek is activated, the SK station is often far away, so it is difficult to switch to DX mode under normal reception mode. Since the SK seek is performed directly in the DX mode, the user can quickly catch the SK station with a weak electric field and quickly complete the seek operation. I didn't have to feel the pleasure for a long time, and I was able to catch it.
If the SK station has already started broadcasting traffic information,
You can listen to this immediately.

Although the above embodiment has been explained using the case of performing SK seek as an example, this invention is not limited to this in any way and can be applied to BK seek and DX seek as well.
In addition to the West German traffic information broadcasting system,
It may be applied when seeking a specific station distinguished by an identification signal in the USA ARI broadcasting system or RDS system.

[Effect of idea]

According to the receiver according to this invention, there is a receiving means for receiving a predetermined band according to variable control of the receiving frequency, a receiving sensitivity switching means for switching the receiving sensitivity of the receiving means, and the receiving sensitivity switching operation means. receiving sensitivity switching means for switching the receiving sensitivity of the receiving means to high or low according to the operation or a predetermined control input; identification signal detecting means for detecting a predetermined identification signal transmitted from a specific station; a seek instruction operating means; and when a seek is instructed by the seek instruction operating means, the receiving sensitivity remains as before, and variable control of the receiving frequency is performed on the receiving means while monitoring the detection output of the identification signal detecting means; conduct,
a first seek control means for seeking a specific station by stopping variable control of the reception frequency when an identification signal is detected; When a seek is performed under the control of the seek control means and an identification signal transmitting station is not found within the band, the receiving sensitivity switching means is controlled to switch to the high sensitivity side, and then the identification signal detection means detects again. and second seek control means for performing variable control of the receiving frequency on the receiving means while monitoring the output, and for seeking a specific station by stopping the variable control of the receiving frequency when the identification signal is detected. Therefore, if a specific station cannot be detected even if the receiver performs a seek with low reception sensitivity according to the user's operation, the reception sensitivity is automatically increased and the seek is performed again.
Even stations that could not be detected due to weak electric field strength if the receiving sensitivity remains low can be picked up, which has the excellent effect of ensuring that necessary information can be heard.

In addition, when the vehicle is driving in the suburbs and has been receiving normal reception with high sensitivity, when starting a seek for a specific station, the specific station is often far away, and If the sensitivity is high, the specific station can be sought under high sensitivity.
If there is a specific station with a weak electric field, it can be caught quickly and the seek operation can be completed quickly, so the user does not feel discomfort due to repeated intermittent reception during seek, and it is possible to catch it as soon as possible. It also has the excellent effect of allowing you to quickly listen to the broadcast of a specific station.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a car radio for a traffic information broadcasting system according to an embodiment of this invention, Figs. 2 and 3 are flowcharts showing the operation of the microcomputer in Fig. 1, and Fig. 4 is a conventional car radio. FIG. 2 is a block diagram of a car radio for a traffic information broadcasting system. 12...Radio receiving unit, 14A...Microcomputer, 16A...Operation unit, 18...
LOCAL/DX switching circuit, 20...LOCAL/DX
Changeover switch, 24...Identification signal detection circuit.

Claims (1)

[Claims for Utility Model Registration] Receiving means for receiving a predetermined band according to variable control of the receiving frequency; Receiving sensitivity switching operating means for switching the receiving sensitivity of the receiving means; Receiving sensitivity switching means for switching the receiving sensitivity of the receiving means to high or low according to an operation or a predetermined control input; identification signal detection means for detecting a predetermined identification signal transmitted from a specific station; and a seeker for instructing to seek a specific station. Instruction operation means: When a seek is instructed by the seek instruction operation means, the reception sensitivity is left as before and the reception frequency is controlled to be variable for the reception means while monitoring the detection output of the identification signal detection means. , a first seek control means for seeking a specific station by stopping variable control of the receiving frequency when an identification signal is detected; 1. When a seek is performed under the control of the seek control means and no identification signal transmitting station is found within the band, the receiving sensitivity switching means is controlled to switch to the high sensitivity side, and then the identification signal detection means is switched again. a second seek control means for performing variable control of the receiving frequency on the receiving means while monitoring the detection output, and for seeking a specific station by stopping the variable control of the receiving frequency when the identification signal is detected; A receiver characterized by: