JPH0243380B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a tuning method for an electronically tuned car radio that can receive roadside traffic information in addition to general broadcasts.

Prior Art and Problems Recently, a roadside traffic information service is about to be started in which a radiator such as a leaky cable is installed along the roadside of a specific road to provide road traffic information to traveling vehicles.

Those who wish to receive this service must find a sign indicating the service area and tune the general broadcasting frequency to the specific frequency for the service, but finding the sign may be delayed or Even if this is detected early, if the synchronization operation is delayed due to the inability to take one's hands off the driver, there is a risk that the service will be missed. In particular, since the service frequency is on the high frequency side outside the general AM broadcasting frequency band, tuning operations tend to be time-consuming. In addition, the service frequency is 1620KHz as the original side.
However, in case the radio wave condition is bad, 1629K
Since it is planned to use a spare frequency of Hz, if it is not possible to tune to the former frequency, it is necessary to try to tune to the spare frequency, which makes the tuning operation even more time-consuming.

1620K preset buttons that have traditionally been used
By adding two buttons for Hz and 1629KHz, tuning operations can be performed easily and quickly, but the number of preset buttons on current car radios has already reached its limit, so adding these new buttons is necessary. is quite difficult. Furthermore, even if a preset button could be added, if the user overlooks the service area sign, he or she will still miss the opportunity to receive service.

Purpose of the Invention The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to provide a car that can receive roadside traffic information service for a predetermined period of time with simple operation without requiring the addition of preset buttons. The purpose is to provide radio.

Structure of the Invention In order to achieve the above object, the present invention changes the tuning digital amount to roadside traffic when a predetermined period of time has elapsed since the change in the tuning digital amount, or when a service request is made again before the predetermined time has elapsed. Change the frequency from one that corresponds to the information service frequency to one that corresponds to the reserve frequency for roadside traffic information service; further service after a predetermined period of time has elapsed since the change in the digital amount for tuning, or before the predetermined period of time has elapsed. When a request or return request is made, the tuning digital quantity is returned to the value before the first service request was made.

Further details of the present invention will be explained below using Examples.

Embodiment of the Invention FIG. 1 is a block diagram of an electronically tuned car radio to which an embodiment of the present invention is applied. This electronically tuned car radio stores a digital value corresponding to each tuned frequency, reads out the corresponding digital value based on an external tuning designation, and operates a phase-locked loop based on the read digital value. It is configured to select stations by changing the frequency division ratio, and includes FM for FM reception, AM reception section AM, phase lock loop circuit PLL, display circuit DIS, display drive circuit DDR, switch SW, audio amplifier circuit.
AA, control circuit that controls the operation of these parts
CONT and a key matrix KMX for inputting control commands to this control circuit CONT.

The FM receiver FM and the AM receiver AM consist of a radio frequency amplifier RF, a local oscillator LO, and a mixer MIX, respectively.
and an intermediate frequency amplification section IF, and a frequency discriminator DISC and a wave detector DET, respectively.
The control circuit CONT reads the preset channel selection channel number etc. from the key matrix KMX, and correspondingly sets the division ratio N1 to 4-digit digital quantity.
Read the frequency of the corresponding channel displayed by N4 from the memory and apply it to the phase lock loop circuit.
Supply to PLL. In response to this, the phase lock loop circuit PLL controls the oscillation frequency of the local oscillator LO using a known phase lock loop via a low pass filter LPF. When tuning is completed by the tuning process, the OR gate is output from the intermediate frequency amplifier IF.
A notification of the end of tuning is sent to the control circuit CONT via . Each output of the FM receiver FM and the AM receiver AM passes through a switch SW switched by an AM/FM switching signal and an audio amplifier circuit AA.
Supplied to speaker SP. The control circuit CONT is
A signal indicating whether the selected signal is FM or AM, 4-digit digital display signals D1 to D4 corresponding to N1 to N4 are displayed by the display drive circuit DDR.
It is supplied to the display circuit DIS through. Also the control circuit
CONT, when neither FM nor AM is selected,
A display drive circuit that displays a digital signal that displays the time and a signal that indicates that the time display is selected.
Output to display circuit DIS via DDR.

Figure 2 shows the key matrix KMX in Figure 1.
FIG. 2 is a conceptual diagram showing an example of the types and arrangement of push buttons. The meaning of each push button in the figure is as follows.

ASU (Auto Search Up): Automatic upward selection ASD (Auto Search Down): Automatic downward selection MSU (Manual Search Up): Manual upward selection MSD (Manual Search Down): Manual downward selection Channel number Reject (Rejection) : Exclusion of specific frequency Write: Trigger for updating preset contents Recall: Request for roadside traffic information service Return: Return Whether or not each push button in each row is pressed is determined by the control circuit CONT at each timing T1 to T4.
It is scanned and read by.

3, 4, and 5 are time charts and flow charts for explaining the operation of the embodiment shown in FIG. 1.

First, when the power is turned on, the control operation of CONT is started, and in block 1, initial settings of the RAM, I/O ports, etc. are performed. Next, the process proceeds to decision block 2, where it is determined whether or not the interval timer has elapsed. As shown in the time chart of FIG. 3, this interval timer is a clock pulse with a constant period (for example, 1 ms). After waiting for the interval timer to elapse, the program proceeds to block 3, where all five timing signals T1 to T5 shown in FIG. 3 are raised to high. The program then proceeds to block 4, where it is determined whether timing signal T5 is low. Immediately after the start of operation, the timing signal T5 is high, so the process proceeds to block 5, where the first digit N1 of the four-digit frequency division ratio N is output from the controller to the PLL. Next, in block 6, the first timing signal T1 falls to low, and in the next block 7, the display segment signal D1 corresponding to N1 is output to the display drive circuit DDR.

In the next block 8, information ASU~ to be read from KMX when timing T1 is low.
Read MSD and store it in RAM. In block 9, the process waits for the interval timer to elapse, and then proceeds to decision block 10, where it is determined whether or not there is a command to dim the display. If a command to dim the display has been issued,
In block 11, the timing signal T1 is raised to high and the display segment signal D1 is turned off, and then the process moves to block 11 and the timing signal is counted up. On the other hand, if a display dimming command has not been issued, block 10 directly proceeds to block 12. Thereafter, the program returns to block 2, waits for the interval timer to elapse, and then advances to block 3, where the timing signal T2 is raised to high. Similarly, when the display segment signal D corresponding to the N value from block 2 to block 12 has been output from the first digit to the fourth digit, the timing signal T5 falls to low in block 3. Control is transferred from decision block 4 to decision block 13.

In decision block 13, it is determined whether the car radio is in the on state or not, and if it is not in the on state, a mute output is performed. If the car radio is in the on state, it is determined in block 14 whether or not it is in the on state for the first time, and if it is likely to be in the on state, a predetermined channel selection process is performed. If the ASU button is not on for the first time, the process moves to block 15, where it is determined whether or not the ASU button has been pressed down. If it has been pressed down, a predetermined search process is performed, and if not, the process moves to the next block. Hereafter, while performing similar push button determination and processing (blocks in the middle are omitted), block 16 is executed.
, select the preset channel number CH1
- Determine whether or not the CH5 push button is in the on state, and perform corresponding channel selection preset reception for those that are in the on state.

The process then proceeds to block 17 of FIG. 5, where the count value of the status counter is determined. This status counter is provided in the control circuit CONT, and as shown in FIG. ”, and if the service request button is subsequently pressed or a predetermined period of time elapses without the service request button being pressed, the value changes from “1” to “2”. When a predetermined period of time has elapsed since the count value reached "2", it returns to "0". Further, when the count value is in the state of "1" or "2", when the return request push button (Return) is pressed, it returns to "0".

If the count value of the status counter is "1", the process advances to block 18, where the frequency being received is
Determine whether it is 1620KHz. If the frequency being received is not 1620KHz, proceed to block 19;
Here, the frequency division ratio N corresponding to the frequency currently being received is saved from the output register to the save register.
Next, in block 20, the frequency division ratio N corresponding to 1620 KHz is read out from the memory and set in the output register, and in block 21, a timer for determining a predetermined reception time is started, and then in block 2 of FIG. Return to The new frequency division ratio N set in the output register is transferred from the control circuit CONT to the phase lock loop PLL by the operation shown in FIG.
is output to.

In block 18, the frequency currently being received is
If it is 1620KHz, the process proceeds to block 22, where it is determined whether the timer started in block 21 has timed up. If the time is not up,
The process then returns to block 2 in FIG. On the other hand, if the time has increased, the process advances to block 23, where the count value is increased from "1" to "2", and the process returns to block 2 in FIG.

When it is determined in block 17 that the count value of the status counter is "2", the process moves to block 24, where it is determined whether the frequency currently being received is 1629 KHz. If it is not 1629KHz,
After reading the frequency division ratio N corresponding to 1629 KHz from the memory and setting it in the output register and starting a timer for determining a predetermined receiving time in block 26, the process returns to block 2 in FIG. The new frequency division ratio N set in the output register is
By the operation shown in the figure, the control circuit CONT outputs the signal to the phase lock loop PLL.

On the other hand, if it is determined in block 24 that the frequency currently being received is 1629 KHz, the process moves to decision block 29, where it is determined whether or not the timer started in block 26 has timed up. If the time-up has not occurred, the program continues as is; if the time-up has occurred, the program returns to the original broadcasting frequency at block 30, and then returns to block 2 in FIG.

If it is determined in block 17 that the count value of the state counter is "0", the process moves to block 27. In block 27, it is determined whether or not a return request push button (Retrurn) was pressed immediately before. When the return request push button is pressed, a flag indicating that the push button has been pressed for a predetermined period of time is set. When it is determined by this flag that the button was pressed immediately before, the blocks 27 to 28
Then, in block 19, the frequency division ratio N corresponding to the original broadcasting frequency saved in the save register is set in the output register. On the other hand, if it is determined in block 27 that the return request push button was not pressed immediately before, the process proceeds to block 2 in FIG.
Return to

FIG. 7 is a state transition diagram for explaining another embodiment of the present invention. When the service request push button (Recall) is pressed for the first time, it changes from "0" to "1" by the program, and the service request push button is pressed again or the service request push button is not pressed again for a predetermined period of time. After the passage of time,
Changes from “1” to “2”. When a predetermined period of time elapses after the count value reaches “2” or if the service request button is pressed again before that time, the count value becomes “0”.
Return to To perform such an operation, when the count value is "2" in the flowchart of Fig. 5, the service request button is pressed again and the flag returns to "0", and then the flag is set for a predetermined period of time. This flag may be set to 1, and in block 27 it may be determined based on this flag that a return request has been made. A return request push button (Return) is added as necessary, so that if the return request push button (Return) is pressed while the count value is in the state of "1" or "2", it returns to "0". It's okay.

Effects of the Invention As explained in detail above, the present invention enables sequential processing of service requests depending on the number of times one service request button is pressed.
Since it can be tuned to 1620KHz and 1629KHz, it can be quickly tuned to the frequency of the roadside traffic information service by simply pressing a button, and it will automatically return to the original broadcasting frequency after a predetermined period of time has passed after tuning. This has the advantage that roadside traffic information, in which short announcements are repeated, can be heard within the necessary minimum range.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an electronically tuned car radio to which an embodiment of the present invention is applied, and FIG.
Fig. 3 is a time chart showing an example of the operation of the electronically tuned car radio shown in Fig. 1, and Figs. A flowchart for explaining the operation of the electronically tuned car radio shown in Figure 1.
6 and 7 are state transition diagrams for explaining the operation of the present invention. FM...FM receiver, AM...AM receiver, PLL...
Phase lock loop, DIS...display circuit, DDR...display drive circuit, SW...switch, AA...audio amplifier circuit, CONT...control circuit, KMX...key matrix, RF...radio frequency amplifier, LO...local oscillator, MIX...mixer , IF...Intermediate frequency amplification section, DISC
...Frequency discriminator, DET...detector, LPF...low pass filter.

Claims (1)

[Claims] 1. A tuning digital amount corresponding to each tuning frequency is stored, a corresponding tuning digital amount is read out based on an external tuning designation, and the read tuning digital amount is used. In the tuning method of an electronically tuned car radio, which selects a channel by changing the frequency division ratio of a phase-locked loop, general broadcasting frequencies, frequencies for roadside traffic information services, and the roadside traffic information are used as tuning digital quantities. The service frequency corresponding to the backup frequency is memorized, and when a service request to receive roadside traffic information service is received, the digital amount for tuning is stored to correspond to the general broadcasting frequency being received. If a predetermined period of time has elapsed since the change in the digital amount for tuning, or if a service request is made again before the predetermined time has elapsed, the digital amount for tuning change the frequency from one corresponding to the frequency for roadside traffic information service to one corresponding to the reserve frequency for roadside traffic information service, and either a predetermined period of time has elapsed since the change in the tuning digital amount, or the predetermined period of time has elapsed. This tuning method for an electronically tuned car radio is characterized in that when a further service request or restoration request is made before the first service request is made, the digital amount for tuning is returned to the value before the first service request is made.