JPS6050089B2 - Channel number display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a channel number display device for a television receiver or the like.

In tuners such as television receivers, variable capacitance elements such as varicaps are used as tuning elements.
So-called electronic tuning tuners, which tune by changing the voltage applied to them, are widely used, and are useful for extending the lifespan of tuners, reducing costs, and making remote control easier.

In this way, in electronic tuning tuners, in order to accurately memorize the preset tuning voltage and always perform correct channel tuning, the tuning voltage when a predetermined tuning state is obtained by the preset operation is converted into a digital code. This is a so-called voltage synthesizer that stores the digital code corresponding to that channel when selecting a channel, and generates a predetermined tuning voltage using a DA converter (digital-to-analog converter) to use as the tuning voltage of the tuner. Many methods are used. However, in electronic tuning tuners, the tuning voltage corresponding to each channel is not always the same voltage due to variations in the characteristics of tuning elements such as varicaps, and the voltage varies depending on the tuner. It is difficult to directly determine the channel number from the stored tuning voltage code.

It is also possible to adjust each tuner so that the channel number is determined from a preset digital code, but if the characteristics of the varicap change over time, the tuning voltage for the same channel may change. , the channel number will also be incorrect.

Therefore, a device has been proposed that displays the channel number directly from the frequency of the tuner's local oscillator.

FIG. 1 shows an example of such a channel number display device.

In the figure, 1 is an electronic tuning tuner, and 2 is a surface acoustic wave element (hereinafter referred to as a SAW element), the details of which will be described later.

3 is a detection amplifier circuit, 4 is a waveform shaping circuit, 5 is a frequency divider circuit, 6 is a counter, 7 is a pulse generation circuit, 8 is a preset switch, and 9 is a tuning determination circuit, which are used for the AGC, . It generates a signal, such as an AFC voltage, in response to a radio wave power signal.

10 is a gate circuit, 11 is a counter, 12 is a channel selection switch, 13 is an encoder, 14 is a storage device, 15 is a D-A
Converter, 16 is a tuning voltage reset circuit, and 17 is a channel number display device.

Next, we will discuss the operation of this device, but first we will explain the operation of this device.
The AW element 2 will be explained.

For example, as shown in FIG. 2, this element has a pair of input electrodes 18, 1", 18" having a comb-shaped electrode structure, and input electrodes 18 to 18 on the surface of a substrate S made of a suitable piezoelectric material.
A plurality of parallel-connected output electrode pairs 19 corresponding to
, 19'', 19''. In this example, the electrode pair 18, 19 corresponds to the television channel VI (F' low band, electrode pair 18'', 19'').
corresponds to the VHF high band, and electrode pairs 18'' and 19'' correspond to the UHF band. When a high frequency signal is applied to the input terminal 1N, the electrical signal is transmitted to the input electrode pairs 18 to 1.
8'' into a surface wave, which propagates on the substrate S and reaches the output electrode pairs 19-19'', where it is again converted into an electrical signal.

At this time, the output electrode pairs 19-19'' are composed of a plurality of electrode pairs, and electrical signals from these pairs appear in parallel at the output terminal 0ut.

Therefore, let the distance between multiple electrode pairs be D, and this distance D
When the time for the surface wave to propagate is γ, the voltage generated at each output electrode pair 19~19'' is as follows.Here, ■1 is the electrode closer to the input electrode pair 18~18'' The output voltage from the pair, V2, is the output voltage from the far electrode pair, ω=2πf (where f· is the frequency of the input signal).

Since the voltages from these electrode pairs are applied in parallel to the output terminal 0ut, if the output voltage of the terminal 0ut is ■, then
, and its absolute value is .

In other words, the absolute value of the voltage ■ obtained at the output terminal 0ut is 1
(2) 1 becomes maximum when N/τ (N is an integer), and the interval between its peak points is constant at 1/τ.

The frequency band of the signal at this time can be determined by the electrode spacing d and the number n of electrode pairs; increasing the electrode spacing d lowers the center frequency, and increasing the number n of electrode pairs narrows the bandwidth.

Therefore, the distance D is selected so that τ = 112 μSec, and the electrode spacing d corresponding to the signal of each band is adjusted to match the local oscillation frequency band of each band. For pairs 18 and 19, the pressure is 150-162M for the positive low band, for electrode pair 1', 19', it is 230-276MHZ1 for the VHF high band, and for electrode pair 1.8'' and 19'', it is 530-824 for the UlIF band.
By determining the value to match the M ratio, this SAW element 2 exhibits a comb-shaped frequency characteristic as shown in FIGS. 3a to 3c. At this time, the first peak on the low frequency side of the comb-shaped frequency characteristic should enter the passband from a point lower than the channel with the lowest frequency in each band by 2 peak points. . In this example, all the electrode pairs 18, 18'', 18'' and 19, for the VHF low band, ■beat high band, and UlIF band are arranged on one substrate S as the SAW element 2 in this example.
19'' and 192 are provided, but it is clear that these may be provided on separate substrates, and the input and output electrode pairs of each band are all connected in parallel. Each acts as a comb filter within its corresponding band, and exhibits almost infinite impedance in other bands, so there is no risk of mutual interference.
It goes without saying that a switch may be used, for example, so that only the signals of the corresponding band are supplied and taken out.

Now, let's move on to an explanation of the operation of the entire device.

First, the tuning must be preset before the tuning operation.

Therefore, any push button switch of the channel selection switch 12,
For example, press the first switch.

At this time, the counters 6 and 11 have been reset in advance. This counter 11 is, for example, 14 bits, and the lower 12 bits give a tuning voltage, the upper 2 bits give reband, and the lower 12 bits give a tuning voltage.
When all bits are 0, the tuning voltage is 0■, and all bits are 1
When , the tuning voltage becomes the maximum voltage in each band, and the upper two bits are "00", [01], and "10".
VI+l' low band, VHF high band,
Represents the UHF band. Therefore, when the counter 11 is reset, the electronic tuning tuner 1 is switched such that the VHF low band is received and the tuning voltage is 0V.
becomes.

When the preset switch 8 is pressed here, the gate circuit 10 opens and the pulses generated by the pulse generating circuit 7 begin to be supplied to the pulse counter 11, the counter 11 starts counting, and the data value increases sequentially.

This data value, that is, the count value is sent to the D-A converter 15.
Since it is converted into an analog signal, that is, a direct current tuning voltage, and applied to the electronic tuning tuner 1, the tuner 1
The tuning frequency increases with each pulse from the pulse generator 7, and when it reaches the point where it tunes to the lowest frequency television channel in the band, for example CH 1, the broadcast wave is received. It becomes like this. When the signal is received by the television receiver, the tuning determination circuit 9 operates, supplies the signal to the gate circuit 10, and closes the gate circuit 10.

As a result, the counter 11 stops counting, its output data value remains unchanged, and the tuning voltage applied from the DA converter 15 to the tuner 1 remains tuned to the broadcast wave of 1CH.

At this time, since an address signal corresponding to the push button of the channel selection switch 12 is applied to the storage device 14 via the encoder 13, the data value of the counter 11, that is, 1CH, is stored at the designated address of the storage device 14. The count value required for the D/A converter 15 to generate a tuning voltage for the broadcast wave is stored. This completes the presetting for 1CH, and from now on, by pressing the push button of the channel selection switch 12 when selecting a channel, the encoder 1
3 specifies the address, and 1CH from the storage device 14
The data value is read out, and a tuning voltage necessary to receive one channel of broadcast waves from the DA converter 15 is applied to the electronic tuner 1, and tuning is performed.

Now, the local oscillator signal from electronically tuned tuner 1 is SAW
Since it is supplied to the input of element 2, during the above presetting, the local oscillator signal increases from a low frequency according to the data of counter 11, and the frequency corresponding to 1CH,
In other words, as can be understood from FIG. 3a, a signal having three peak values appears at the output of the SAW element 2 until it reaches 150 M field. This signal is transmitted to the detection amplifier circuit 3.
After being detected and amplified by the waveform shaping circuit 4, the waveform is shaped into a pulse by the waveform shaping circuit 4, and is supplied to the counter 6 via the frequency divider circuit 5. Therefore, the pulse is stored in the counter 6 by the time it is preset to 1CH. is supplied to the channel number display device 1 which displays the output data of the counter 6.
7 indicates that it is 1CH.
Therefore, even at the time of presetting, it can be known that the selected broadcast wave is for 1CH.

Next, press the second push button of the channel selection switch 12, then press the preset switch 8 to supply a pulse to the counter 11, and increase the tuning voltage from the D-A converter 15. , for example, a 3CH broadcast wave is received, and the data of the counter 11 is stored and preset at the address corresponding to the second push button of the storage device 14.

At this time, since the frequency of the local oscillator signal has reached 162 MHZ, signals having peak values in six amplitudes are obtained at the output of the SAW element 2 from the time of 1CH, and the shaping circuit 3 divides the frequency dividing circuit 5. Then, two pulses are input to the counter 6, and its output data counts 2 in addition to 1, and 3.
becomes.

Therefore, it is displayed that 3CH has been preset. In this way, presetting is performed for each channel one after another, and when the highest frequency in that band is reached, the upper two bits of the counter 11 change to "O month", the switch is switched to the VHF high band, and the lower two bits are all set to 0. The tuning voltage rises again from 0■, and reaches 4C.
Presetting of channels H to 12 is performed, and at the same time, the channel numbers are sequentially displayed on the display device 17. When the upper two bits of the counter 11 become "10" and the switch is made to the UHF band, presetting is performed in the same way, and once the presetting of the highest frequency channel W1 in band 2, for example 62CH, is completed, The preset state is canceled, and from now on, the user can select any desired channel by operating the channel selection switch 12.

Now, when performing a channel selection operation, press the button of the channel to be selected from among the push buttons of the channel selection switch 12. When the button is pressed, the encoder 13 reads out from the storage device 14 the band and tuning voltage code of the address corresponding to the button.

At the same time, a tuning signal from the encoder 13 is also generated.
The tuning voltage reset circuit 16 is operated to temporarily reset the tuning voltage applied to the tuner 1 to 0V, and then return it to the tuning voltage given from the storage device 14 and converted by the DA converter 15. . At this time, the operation of the reset circuit 16 is set to have a time constant using, for example, a CR circuit, so that the local oscillation frequency of the tuner 1 is swept and increased at a predetermined speed. Now, if the selected push button is for 3CH, the local oscillation signal increases to 162 MHz.

Therefore, as is clear from FIG. 3a, the number of amplitude peaks appearing in the output of the SAW element 2 is nine, and the number of input pulses to the counter 6 is three, so the count output is 3, which is 3CH. This is displayed on the display device 17. The channel selection operation for other channels is performed in exactly the same way, and the channels are displayed, but V8 high band and U
In the HF' band, unlike when presetting, the counter 6 does not contain the count input when presetting to the previous channel, so the VH
The counter 6 must be preset to 3 for the F high band and 12 for the UHF band.

The reason for this is, as is clear from Figure 3 B and c, ■HF
The lowest frequency channels of the high band and U8 band are each 4CH113CH, but the counter 6
This is because only one pulse is input to each input during channel selection. In this way, according to the device shown in Figure 1, the channel number is displayed directly from the local oscillator signal, so the electronic tuning tuner and voltage synthesizer system enables preset tuning and always accurate channel display. can be made to do so. By the way, in such a channel display device, it is difficult to make the sweep speed of the tuning voltage supplied to the electronic tuning tuner 1, that is, the rate of increase, the same at the time of presetting and at the time of channel selection.

That is, at the time of presetting, the tuning determination circuit 9 must be able to reliably detect the tuning point, so the tuning voltage must be increased at a relatively slow speed.

Specifically, the frequency of the pulses from the pulse generating circuit 7 must be fairly low.

On the other hand, when selecting a channel, the tuning voltage to be reached is determined in advance by D.
-A converter 15, and if it takes a long time from when the push button of the channel selection switch 12 is pressed until the channel is actually selected and the television image is changed, it is not practical. The time constant of the tuning voltage reset circuit 16 is determined so that the tuning voltage increases as quickly as the design allows.

As a concrete value, if you select the highest channel in the UHF band, the time it takes for the tuning voltage to reach that point is:
It is selected to be around 100rrLSeC.

Therefore, in this case, the output level of the detection amplifier circuit 3 is 100Tt. It changes with about 150 peak points during sec (see Figure 3). Therefore, let f be the frequency of the level change.

On the other hand, when presetting, as mentioned above, it must probably be on the order of a few Hz to 10 Hz.

Therefore, if an AC amplifier type one is used as the detection amplifier circuit 3, there will be no problem when selecting a channel, but when presetting, the frequency of the signal to be amplified is too low.
It becomes difficult to amplify to a level that can be shaped by the waveform shaping circuit 4, and the probability that the counter 6 malfunctions during presetting becomes extremely high, making it impossible to obtain accurate channel display. In order to improve this, in order to be able to amplify even low frequency signals, even if a DC amplifier type one is used, the required gain is quite high.
This requires careful consideration of power supply drift, temperature drift, etc., which has the drawback of being a major factor in increasing costs.

SUMMARY OF THE INVENTION An object of the present invention is to provide a channel number display device that is inexpensive and can display accurate channel numbers even during presetting, while eliminating the drawbacks of the prior art described above.

To achieve this objective, the present invention displays the channel number during presetting only immediately after the broadcast wave of each channel is received and the tuning voltage stops increasing, and during other periods only the display indicating the preset is displayed. It is characterized by what it does.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 4 is a block diagram showing one embodiment of the present invention, in which the same or equivalent parts as in FIG. 1 are given the same numbers.
This embodiment differs from the device shown in FIG. 1 in that a counter 6, a tuning voltage reset circuit 16, and a channel number display device 17 are controlled by a tuning determination circuit 9. . That is, the counter 6 is also reset by a signal from the determination circuit 9.

When a signal is applied from the determination circuit 9, the reset circuit 16 operates at the rising edge of the signal, temporarily returns the tuning voltage supplied to the electronic tuning tuner 1 to 0V, and then resets the counter at the same speed as when selecting a channel. 11, raise and return to the tuning voltage given by the DA converter 15. The channel number display device 17 displays the counter 6 when there is no signal from the determination circuit 9, that is, until a broadcast wave is obtained.
Since the output data of is not displayed, it is displayed that presetting is in progress.

For example, if the display device 17 is a 2-digit display device using a 7-segment numeric display element, the only display blanking and the first display will be "P" representing the capital letter P of the alphabet. It is better to display it. Incidentally, as in the case of FIG. 1, the tuning determination circuit 9 generates a signal at its output when a broadcast wave is received by the television receiver at a predetermined level or higher.

The other parts are the same as the apparatus shown in FIG.

Next, the operation of this device will be explained.

As in the case of Fig. 1, when presetting, press the first push button of the tuning switch 12 and press the preset switch 8, the gate circuit 10 opens and the counter 11 operates, sweeping up the tuning voltage. ■ When tuned to the first channel of the HF low band, for example, CH 1, the broadcast wave is received, the determination circuit 9 generates a signal, and the gate circuit 1
0 and keep the tuning voltage at that voltage.

Then, the data of the counter 11 at this time is stored in the address of the storage device 14 specified by the encoder 13,
Preset. However, the preset switch 8 opens the gate circuit 10 and the tuning voltage begins to rise.
Since no signal output is generated from the determination circuit 9 until the broadcast wave is received, the display device 17 only indicates that it is in the preset state and does not display the output of the counter 6. For example, it is displayed as "P".

Therefore, since the detection amplifier circuit 3 is of the AC amplifier type, even if the counter 6 malfunctions, it will not affect the display at all. When the tuning voltage reaches a predetermined value and the broadcast wave is received, and the tuning determination circuit 9 generates a signal, the tuning voltage reset circuit 16 operates in response to the rising edge of the signal, and temporarily resets the tuning voltage. Reset to 0■.

Then, the voltage is swept up again to the tuning voltage given by the counter 11. At this time, since the signal of the determination circuit 9 is also given to the counter 6 and the display device 17, the counter 6 is reset at the rising edge of the signal, and at the same time, the display device 17 changes from the "P" display operation which is the preset display. It has been canceled and the operation has been switched to displaying the output of the counter 6. Therefore, as the frequency of the local oscillation signal of the electronic tuning tuner 1 sweeps up due to the increasing tuning voltage applied by the counter 11 after reset, the number of peak points occurring in the output of the SAW element 2 increases. The determined pulse number is counted again by the counter 6 and given to the display device 17, where it is displayed as a channel number.

At this time, the speed of the tuning voltage sweep rise is as follows. It is independent of the period of pulse generation from the pulse generation circuit 7, and is determined by the time constant characteristics given to the reset circuit 16.
It has sufficient speed, which is the same as the speed during channel selection operation.

Therefore, the signal to be amplified by the detection amplifier circuit 3 has a sufficiently high frequency, . For example, it is 1.5KHZ and can be handled sufficiently by a normal AC amplifier, so it is possible to give an input of a sufficient level for the waveform shaping circuit 4 to operate, and the counter 6 may malfunction and the channel number is There is no fear that the display will go awry. Next, if you press the second push button of the channel selection switch 12 and then press the preset switch 8, the display on the display device 17 will change to “
When the broadcast wave is received, the presetting for that channel is completed, and the display on the display device 17 changes to "P".
", the display changes to the number of that channel, for example "3", and remains in that state until moving to the next preset. FIG. 5 shows the changes in the tuning voltage and the display state at this time. If the first push button of the channel selection switch 12 and the preset switch 8 are pressed at that time, then
At the same time that the display on the display device 17 becomes "P", the tuning voltage of the tuner 1 increases linearly at a relatively slow speed according to the pulse generation cycle from the pulse generation circuit 7, and the local oscillation signal The frequency also increases.

Eventually, after a predetermined period of time has elapsed, the tuning voltage necessary for tuning the 1CH speed wave is reached at the time, and when the determination circuit 9 generates a signal, the reset circuit 16 operates and the tuning voltage becomes 0V.
, and the display on the display device 17 is switched from "P" to the display of the output of the counter 6, which is reset at the same time.

After that, the tuning voltage rises and returns to the voltage corresponding to 1CH in the time determined by the reset circuit 16 from time t1 to T2, and the counter 6 counts the change in the local frequency at this time. The output becomes 1, and the display device 17 displays channel number 1.

Next, if the second push button of the channel selection switch 12 and the reset switch 8 are pressed at a certain time, the display state changes to "P" again, and the tuning voltage slowly rises in a straight line. The frequency of the local oscillator signal also increases and reaches the voltage at which the next channel's broadcast wave is received at time ζ.

As a result, the tuning voltage is momentarily reset to 0V again,
The counter 6 is also reset, and the display on the display device 17 shows "
"P" disappears and the display changes to the count status, and when the time reaches 3C
H will be displayed.

Note that the tuning voltage and data representing the band for the storage device 14 are preset at times t1 and ζ, respectively, but these may be determined arbitrarily.

As explained above, according to this embodiment, even during presetting, the frequency of the input pulse of the counter 6 for displaying the channel number is maintained at a sufficiently high value, so that it is possible to As in the case of a channel number display device, it is possible to prevent the operation of displaying an incorrect number on a channel due to a malfunction of a counter, and it is possible to use an AC amplifier, thereby eliminating a factor of cost increase.
Now, in the embodiment shown in FIG. 4, a so-called search preset method is adopted in which the rise in the tuning voltage is stopped each time a broadcast wave is received during presetting, and a code is stored in the storage device each time. However, the preset method is a so-called automatic method that continuously stores all receivable channels of all bands while sweeping up the tuning voltage without stopping the voltage increase each time. A preset method is also known. Therefore, an embodiment in which the present invention is applied to an automatic preset method will be described. For example, in this embodiment, the output of the tuning determination circuit 9 is added to the counter 6, the gate circuit 10, the tuning voltage reset circuit 16, and the channel display circuit 17 in the configuration shown in FIG. The output of 9 is used only for the operation of storing the tuning voltage code when the broadcast wave is received at a predetermined address of the storage device 14, and instead, a circuit is provided to determine that all presetting has been completed. The counter 6, gate circuit 10, reset circuit 16, and display device 17 are controlled by this output.

Note that the output signal of the synchronization determination circuit 9 causes the storage device 1 to
The point that the storage operation of the tuning voltage code for 4 is performed is the same in the cases of FIGS. 1 and 4.

Therefore, its operation is as follows.

The preset is performed by increasing the frequency of the local signal by a pulse from the pulse generation circuit 7, and storing a code in each address by the output of the determination circuit 9 when a broadcast wave is received. During this period, no signal appears at the output of the circuit for determining the end of presetting, so the display on the channel number display device 17 is "P".

When the preset is completed for all broadcast receivable channels, the preset is finished and the circuit that determines this generates a signal at its output.

This signal specifies a specific address in the storage device 14, for example, the address corresponding to the first push button, reads out the code, and supplies it to the DA converter 15. At the same time, the tuning voltage reset circuit 16 once resets the tuning voltage to 0.times., and returns it to the voltage of the DA converter 15 again. The frequency change of the local oscillator signal of the tuner 1 accompanying the return operation at this time is extracted as the number of peak points by the SAW element 2, counted by the counter 6 which is reset at the same time, and the preset display is switched to the count display. The channel number is displayed as 1 on the display device 17, and the end of the preset is indicated.

Note that when the preset is finished, the counter 1
The upper 2 bits of 1 data are “10” (i.e. U
HF band), and the lower two bits are all 1 (that is, the tuning voltage is the highest voltage), so the circuit to determine the end of preset can be one that detects the above state and generates an output, which is simple. It can be easily realized by combining various gates.

Therefore, as in the case of the embodiment shown in FIG. 4, the frequency of the signal handled by the detection amplifier circuit 3 is not the frequency at the time of presetting, which is relatively slow, but the frequency at the time of tuning, which changes quite rapidly. Therefore, there is no risk of malfunction in channel number display, and there is no need to use a DC amplifier which increases cost.

Yet another embodiment of the invention is shown in FIG.

This embodiment is a so-called manual preset method in which the operator performs the preset operation while looking at the image plane of the television receiver and finding the tuning point. Parts that are the same or equivalent to those in Figure 1 are given the same numbers. This embodiment is different from the device shown in FIG. 1 in that the counter 11 is of an up-down type, and each of the up-down switching inputs of the counter 11 is equipped with a tuning voltage up switch 20 and a tuning voltage down switch 20. In addition, the outputs of these switches 20 and 21 are applied to the input of a NOR gate 22, and the gate circuit 10 is opened by the output of this NOR gate 22, and the counter 6, The tuning voltage reset circuit 16 is reset, and the channel number display device 17 is switched between displaying the preset and the counter 6. Next, the operation of this device will be explained. First, it is assumed that the first push button in the channel selection switch 12 is pressed, and then the up switch 20 is pressed.

Since the counter 11 has been reset in advance, the electronic tuning tuner 1 is set to the VlIF' low band tuning state, and the output of the switch 20 controls the NOR gate 2.
The output of 2 becomes "0", the gate circuit 10 is opened, and the pulse from the pulse generation circuit 7 is supplied to the counter 11.
The number of output data of the counter 11 increases sequentially.

Therefore, the tuning voltage supplied to the tuner 1 also rises relatively slowly from 0V while the switch 20 is closed, and when it reaches the point where it tunes to the first channel, the broadcast wave is received.

At this time, since the output power of the NOR gate 22 is 0, the display device 17 is in a preset display state, for example, a "P" display state. When the broadcast wave to be preset is received and confirmed on the image plane of the television receiver, the operator opens the switch 20.

This causes the output of the NOR gate 22 to switch to F5, the gate circuit 10 closes and cuts off the pulses being supplied to the input of the counter 11, keeping the tuning voltage intact and storing the output of the counter 11 in the memory 14. Memorize and preset the output.

At the same time, the tuning voltage reset circuit 16 operates when the output of the NOR gate 22 changes from 0 to 1, resets the tuning voltage to 0 for a short time, and compares it to the original value again. Return to the top at a high speed.

Then, when the tuning voltage returns at this time, the counter 6 performs a counting operation and oscillates a signal corresponding to the channel number at the output. Already, at this time, display device 1
7 is switched from the preset display state to the counter display state by the "゜1" output of the NOR gate 22, the display device 17 displays the data of the counter 6 and accurately displays the channel number. The same is true when the switch is pressed; in this case, the tuning voltage that once rose will fall, and when the necessary broadcast wave is received, the switch 21 can be released, and the subsequent display operation is exactly the same as when the switch 20 is pressed. It is.

As explained above, according to the present invention, even if the tuning voltage is changed relatively slowly during presetting, there is no risk that the channel number will be displayed incorrectly. This type of display device can be provided at low cost without the cost increase factor.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a conventional channel number display device using a SAW device, FIG. 2 is a schematic configuration diagram showing an example of a SAW device used in the channel number display device, and FIGS. 3A, b, c is a characteristic diagram showing its frequency characteristics, FIG. 4 is a block diagram of a channel number display device according to an embodiment of the present invention, FIG. 5 is a characteristic curve diagram for explaining its operation, and FIG. 6 is a characteristic curve diagram for explaining its operation. FIG. 2 is a block diagram of a channel number display device according to an embodiment of the present invention. 1...Electronic tuning tuner, 2...SA
W element, 3...Detection amplifier circuit, 4...
Waveform shaping circuit, 5...3 frequency divider circuit, 6...
・Counter, 7... Pulse generation circuit, 8...
... Preset switch, 9 ... Tuning judgment circuit, 10 ... Gate circuit, 11 ... Counter, 12 ... Tuning switch, 13 ...・Encoder, 14...Storage device, 15...
DA converter, 16... Tuning voltage reset circuit, 17... Channel number display device.

Claims (1)

[Scope of Claims] 1. An electronic tuning tuner having a voltage-controlled local oscillator, a storage device for storing a digital signal corresponding to a tuning voltage and a band switching signal applied to the electronic tuning tuner, and A preset tuning device comprising means for storing a digital signal, a surface acoustic wave element receiving the signal from the local oscillator as input, a detector coupled to the output of the element, and inputting the signal from the detector. and a display device which inputs the data of the counter, and displays the channel number according to the number of amplitude changes of the voltage obtained at the output of the detector during channel selection operation,
During the preset operation, the display device displays that the preset operation is in progress, and after the preset operation is completed, the tuning voltage is reset once and the channel number is displayed by returning the voltage to the voltage at the time the preset operation is completed. A channel number display device characterized by: 2. The means for storing digital signals in the storage device includes:
2. The channel number display device according to claim 1, wherein the channel number display device uses a search preset method in which each channel is stored one by one each time a broadcast signal is detected. 3. The means for storing digital signals in the storage device includes:
2. The channel number display device according to claim 1, wherein the channel number display device has an automatic preset method that continuously and automatically stores all receivable broadcast signals in all frequency bands. 4. The means for storing digital signals in the storage device includes:
The channel number display device according to claim 1, characterized in that it is of a manual preset type in which each channel is manually memorized.