JPH0753306Y2 - Electronic tuning tuner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an electronic tuning tuner having an automatic tuning function.

(Prior Art) Conventionally, when the tuning instruction voltage of a voltage substantially proportional to the receiving sensitivity extracted from the intermediate frequency amplifier circuit of the tuner is less than a predetermined value, a phase locked loop (hereinafter referred to as "PLL") is used.
There is an electronic tuning tuner that has an automatic tuning function that performs tuning by varying the tuning voltage supplied to the.

Further, as the applicant previously proposed in Japanese Utility Model Application No. 60-48423, the name of the device "electronic tuning tuner", it has a preset function for presetting the frequency of an arbitrary broadcasting station for each of a plurality of channels, The reception level (tuning instruction voltage) of the selected broadcasting station is below the reference level (reference voltage equivalent to the minimum tuning instruction voltage required for reception), and this state exceeds the set time. Sometimes, there is an electronic tuning tuner that automatically selects another broadcasting station.

When the above-mentioned conventional tuner is used for mounting on a vehicle such as a car stereo, the receiving sensitivity changes as the vehicle runs.

FIGS. 5 (A) and 5 (B) are diagrams showing an example of variation of the tuning instruction voltage (reception level) according to the receiving sensitivity, and FIG. 5 (A) is an example in which the variation of the receiving level is gentle while traveling on the plain. , The figure (B)
Is an example where the reception level fluctuates sharply while driving in a mountainous area or an urban area away from the broadcasting station.

In the plain area, as shown in FIG. 5 (A), the fluctuation of the reception level of the broadcasting station is relatively gentle, and the level does not become extremely high or low as the vehicle runs. In such a place, it is more suitable for the viewer (listener) to set the reference level for starting the automatic channel selection to a low level and continue to receive the broadcasting station having a relatively low reception level.

However, in urban areas away from mountainous areas and broadcasting stations,
As shown in FIG. 6B, as the vehicle runs, the vehicle becomes behind a mountain or a building, and the reception level of the broadcasting station during reception is simply increased or decreased. In such a place, unless the reference level for starting automatic channel selection is set high, the state in which the reception level becomes equal to or lower than the reference level does not continue for the set time, so automatic channel selection is not performed and it is difficult to hear.

(Problems to be solved by the invention) As described above, in the conventional electronic tuning tuner, the automatic tuning that best matches the listener's feeling is performed according to the driving place of the car where the reception level of the broadcasting station is different. There was a problem that I could not do.

(Means for Solving Problems) In order to solve the above problems, the present invention detects the reception sensitivity and detects the reception sensitivity in an electronic tuning tuner that tunes a tuning frequency corresponding to a tuning voltage. Detecting means for obtaining a tuning instruction signal having a level according to sensitivity, comparing means for comparing the level of the tuning instruction signal with a reference level, and timekeeping for timing when the level of the tuning instruction signal becomes smaller than the reference level Means, the first control means for changing the tuning frequency when the time measured by the time measuring means exceeds the first set time, and the time measured by the time measuring means exceeds the second set time. An electronic tuning tuner comprising: counting means for counting the number of times; and second control means for changing the setting of the reference level when the number of times counted by the counting means within the third set time exceeds the set number. provide It is a thing.

Embodiment An embodiment of the electronic tuning tuner according to the present invention will be described below with reference to the drawings.

FIG. 1 is an overall configuration diagram of an electronic tuning tuner. In the figure, an electronic tuning tuner unit Tu performs tuning of a tuning frequency corresponding to a tuning voltage.

The detection means A detects the reception sensitivity and obtains a tuning instruction signal.
The comparison means B compares the level (tuning instruction voltage) V of this tuning instruction signal with a reference level (reference voltage corresponding to the minimum tuning instruction voltage necessary for reception) VS. Initially VS = v is set. The timing means C counts when the level V of the tuning instruction signal becomes smaller than the reference level VS according to the comparison result of the comparison means B. The first control means D is a timing means C
The time set by the first set time T1 (for example, 10
(Seconds), the electronic tuning tuner Tu is controlled to change the tuning frequency. The counting means E counts the number N of times when the time measured by the time measuring means C exceeds the second set time T2 (for example, 3 seconds). The second control means F changes the reference level VS of the comparison means B when the number of times N counted by the counting means E exceeds the set number (eg, 3 times) within the third set time T3 (eg, 15 seconds). (Higher from v to v ').

When the vehicle travels in the plain, the fluctuation of the reception level (level of the tuning instruction signal) of the broadcasting station changes (decreases) relatively gently, and the first condition is that the reception level V is not larger than the reference level VS. When the set time T1 (for example, 10 seconds) continues, the electronic tuning tuner Tu is automatically selected for the next channel.

Also, when traveling in a mountainous area or an urban area away from the broadcasting station, the reception level of the broadcasting station fluctuates significantly, but the first set time T1 (10 seconds) is when the reception level V is not larger than the reference level VS. Does not continue. For example, as shown in FIG. 4, when the reception level V fluctuates near the reference level VS, the state where the reception level V is not larger than the reference level VS continues for the second set time T2 (3 seconds). When the number of continuations exceeds the set number N (3 times) within the third set time T3 (15 seconds), the reference level VS is changed from v to v'high. Therefore, the fluctuation of the reception level V is compared with the reference level v ′, and even if the reception level fluctuates in the vicinity of the conventional reference level v, {the reception level before the change is lower than the reference level v. Is not too large for the first set time T1 (10 seconds), the automatic tuning is not performed and the broadcasting station in the poor reception state is still received}, and received at a level lower than the reference level v '. Since the level fluctuates, the reception level V becomes the reference level v ′.
A state not larger than that continues for the first set time T1 (10 seconds), automatic channel selection is performed, and a broadcasting station with a good reception state is selected.

FIG. 2 shows a block system diagram of the electronic tuning tuner unit Tu shown in FIG. In the figure, a high frequency signal received by an antenna 1 is tuned and amplified by a high frequency amplifier circuit 2 and supplied to a mixing circuit 3. This high frequency signal is mixed with the local oscillation frequency signal from the local oscillation circuit 4 in the mixing circuit 3 to be an intermediate frequency signal. The intermediate frequency signal is amplified by the intermediate frequency amplification circuit 5, demodulated by the demodulation circuit 6 and supplied from the terminal 7 to the next stage circuit.

The oscillator 8 outputs an oscillation signal of a constant frequency. This oscillating signal is divided by a variable frequency divider 10 which varies a frequency division ratio according to a control signal from a controller 9 to be a reference signal, which is supplied to a phase comparator 11. Further, the local oscillation signal output from the local oscillator circuit 4 is frequency-divided by the frequency divider 12 and then the phase comparator.
11 is provided where the phase comparison with the reference signal is performed. The phase comparison error voltage output from the phase comparator 11 has an unnecessary high frequency component removed by the low frequency filter 13, and is supplied to the high frequency amplification circuit 2 and the local oscillation circuit 4 as a tuning voltage. The tuning frequency of the high frequency amplifier circuit 2 and the oscillation frequency of the local oscillation circuit 4 are varied by this tuning voltage.

The operation panel 14 is provided with operation buttons such as a preset search button and a preset button. The operation signals generated by these button operations are supplied to the controller 9. Further, the tuning instruction voltage is supplied from the intermediate frequency amplifier circuit 5 to the controller 9. The tuning instruction voltage is a DC voltage obtained by rectifying the intermediate frequency signal before amplitude limitation and is a voltage substantially proportional to the reception sensitivity (reception level).

FIG. 3 shows a flow chart of an embodiment of processing executed by the controller 9. When the preset search button is operated and the preset search mode {the receiving level (tuning instruction voltage V) is not higher than the reference level (reference voltage VS), the controller 9 selects the broadcasting stations with good receiving sensitivity sequentially from the first channel. }, The processing shown in FIG. 3 is started. It should be noted that FIG. 4 shows an example of fluctuations in the tuning instruction voltage V when a broadcast station is received.

When the preset search mode is set at time t ₀ , the controller 9 sends a control signal for tuning to the preset channel broadcast station selected last at the time of the previous reception or the preset channel broadcast station currently being received. It is generated and supplied to the variable frequency divider 10, whereby the tuning frequency of the high frequency amplifier circuit 2 and the oscillation frequency of the local oscillator circuit 4 are varied, and the broadcasting station of the initial reception channel is tuned and tuned (step 20). Further, variables are initialized (step 20-1). Next step 42 is a step of checking whether or not the counting of the third set time T3 (for example, 15 seconds) is started. During the counting, the flag F is on and the routine proceeds to step 34 where the variable M3 counts up every unit time. To be done.

After that, the tuning instruction voltage V from the intermediate frequency amplifier circuit 5 is compared with the reference voltage VS (= v) (step 21), and when the tuning instruction voltage V becomes large, the value of the variable M1 for counting is reset to zero. (Step 22), the above steps 21, 22, and 42 are repeatedly executed.

When the tuning instruction voltage V becomes smaller than the reference voltage VS (= v) at the time t ₁ (step 21), the flag F is turned on (step 44), the process proceeds to step 23, and the variable M1 counts up every unit time. To be done.

After that, the variable M1 is compared with the set value S1 corresponding to the first set time T1 (for example, 10 seconds) (step 24), and when the value of the variable M1 is not large, the process proceeds to step 30, and the variable M2 is set as the unit time. It is counted up every time. After this, the variable M2 is compared with the set value S2 corresponding to the second set time T2 (for example, 3 seconds) (step 31), and when the value of the variable M2 is not large, the step
Return to 42.

When the tuning instruction voltage V is smaller than the reference VS (= v),
When the t ₁ is continued beyond the second set time T2 (for example, 3 seconds) (time t ₁ '), the value of the variable M2 is larger than the set value S2 (step 31), step 32 and 33 After sequentially shifting, the variable M2 is reset, the variable N is incremented by 1, and the routine proceeds to step 35.

The variable M3 is compared with the set value S3 corresponding to the third set time T3 (for example, 15 seconds) (step 35), and if the value of the variable M3 is large, the process proceeds to step 36, step 37, and step 43 sequentially. The variables M3 and N are reset, the flag F is turned off, and the process returns to step 42. In steps 42 and 21 to 37, the number of times (variable N) that the tuning instruction voltage V is smaller than the reference voltage V (= v) exceeds 3 seconds is counted.

From time t ₁ in the third set time T3 (15 sec) in elapsed, the variable
The value of M3 is not greater than the value of setting S3 (step 3
5), shift to step 38.

Thereafter, the variable N is compared with the set value NS corresponding to the set number of times (for example, three times) (step 38), and when the variable N does not exceed the set value NS, the process returns to step 42. From the time t ₁ the third set time T3 reference tuning command voltage V (15 seconds) in the voltage VS
When the number of times the variable smaller than (= v) exceeds the second set time T2 (3 seconds) (variable N) exceeds 3 (from time t ₁
t ₁ ′, t ₂ to t ₂ ′, t ₃ to t ₃ ′), the variable N becomes larger than the set value NS, and the process proceeds to steps 39 and 40 to reset the variable N and the variable M3. , And shifts to step 41.

In step 41, the reference level VS is reset to a higher reference voltage v ', and after step 43, it returns to step 42.

At time t ₃ ′, the reference voltage VS is increased from v to v ′, the tuning instruction voltage V becomes smaller than the reference voltage VS (= v ′), and this continues for the first set time T1 (10 seconds), Times of Day
At t ₄ , the value of the variable M1 becomes larger than the predetermined value S1 (step 24), the process proceeds to step 25, the values of the variables M1 and M3 are reset to zero, the flag F is turned off, and the reference voltage VS is set at step 26. Returned to the first level from v'to v.

Thereafter, in step 27, the broadcasting station of the first channel is tuned and selected, and the tuning command voltage V and the reference voltage VS (= v)
And are compared (step 28). Here, when the tuning instruction voltage V is high, the process proceeds to step 42, and when it is low, the process proceeds to step 29-1. In steps 29-1 and 29-2, the tuning of the second channel broadcasting station is selected, and the tuning instruction voltage V
When the value becomes larger, the process proceeds to step 42, and when it becomes smaller, the process proceeds to next step 29-3, the broadcasting station of the last channel is selected for tuning, and the process returns to step 42.

(Effect of the device) As described in detail above, in the plain area where the level of the tuning instruction signal (reception level) according to the reception sensitivity is relatively gentle, the reference level is set low, and fluctuations in the reception level occur. The standard level is set high in the severe mountainous areas and urban areas away from broadcasting stations, and automatic tuning is performed according to the appropriate reference level according to the driving location of the car, so automatic tuning that matches the listener's sense is performed. be able to.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of an electronic tuning tuner according to the present invention, FIG. 2 is a block system diagram of the electronic tuning tuner section shown in FIG. 1, and FIG. 3 is shown in FIG. A flow chart of an embodiment of processing executed by the controller, FIG. 4 is an explanatory view showing an example of fluctuation of the tuning instruction voltage when a broadcast station is received, and FIGS. 5 (A) and 5 (B) show conventional problems. It is a figure for explaining and is an explanatory view showing an example of change of tuning directions voltage. 21,28,29-2 …… Step to judge that the reception level (tuning instruction voltage) is not higher than the reference level (voltage),
24 …… Step for judging the elapse of the first set time T1, 31
...... Steps for judging the elapse of the second set time T2, 35 ...
... Step for judging the third set time T3, 38 ... Step for judging elapse of the set number of times N, 41 ... Reference level is v
From V to v ', A ... Detection means, B ...
Comparing means, C ... Timing means, D ... First control means, E
...... Counting means, F ...... Second control means, Tu ...... Electronic tuning tuner section.

Claims (1)

[Scope of utility model registration request] 1. An electronic tuning tuner unit for performing tuning tuning of a tuning frequency corresponding to a tuning voltage, detection means for detecting the receiving sensitivity and obtaining a tuning instruction signal of a level according to the receiving sensitivity, Comparing means for comparing the level of the tuning instruction signal with a reference level, time measuring means for measuring the time when the level of the tuning instruction signal becomes lower than the reference level, and time set by the time measuring means as the first setting. First control means for changing the tuning frequency when the time is exceeded, counting means for counting the number of times the time counted by the time counting means exceeds the second set time, and counting by the counting means An electronic tuning tuner comprising: a second control means for changing the setting of the reference level when the number of times within the third set time exceeds the set number of times.