JPS60245307A - Channel selecting device - Google Patents

Abstract

PURPOSE:To obtain a device having a good operability without making it necessary to execute newly a band selecting operation, by generating a mode setting signal together with switching to a write mode, and setting a receiving band. CONSTITUTION:A channel selecting device generates a band setting signal, when a mode has been set to a write mode by a write/read-out switching circuit 2, and sets a receiving band to some band, for instance, a VHF band at the same time as the band is switched to the write mode by this band setting signal. This device is constituted so that the band setting operation does not occur, when a detecting output is generated by a synchronizing signal detecting circuit 6. In this way, the receiving band can be set by a switching operation of a write/ read/out mode without executing newly a band selecting switch operation. Also, a channel preset operation can be executed efficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a channel selection device for a television receiver. 0 Configuration of conventional example and its problems Most of recent television receivers are electronic channel selection systems. The market is dominated by products with various additional functions. The system targeted by the present invention is equipped with a control circuit consisting of a microcomputer and a non-volatile storage device (hereinafter referred to as memory), and when presetting a channel, by operating a manual tuning switch/notch, from the control circuit.
For example, at the start of a sweep, the signal is equivalent to the tuning voltage ○vvc, and a tuning digital signal that changes every moment is generated from the sweep, and is applied to the tuner as an analog signal tuning voltage through a D-A converter and, if necessary, a DC amplifier. (Accordingly, this tuning voltage also changes in the opposite direction, from low to high.) When a broadcasting channel is received, a horizontal synchronization signal is detected and the phase difference with the flywheel clock is detected. When a match is found, a detection output is issued, the above-mentioned sweeping operation is stopped, and the channel information at this time is stored in the memory. Therefore, at this time the memory is in write mode. This method has the advantage of being able to preset channels more quickly and accurately than conventional means using potentiometers.The above channel selection device will now be described in more detail with reference to FIG. 1. In the figure, 1 is a control circuit composed of a microcomputer and nonvolatile memory, 2 is a write/read mode switching circuit (mode switching switch), and 3
is a band (VHF.

UHF) switching circuit, 4 is a manual tuning switch, 5 is a memory switch, 6 is a synchronization signal detection circuit, which has a terminal to which the flybank pulse HP and synchronization signal 5YNC are input, and when the phases of both signals match, the output became 'H Rubel,
The control circuit 1 is controlled to slow down the sweep speed.

7 is a channel number display device, 8 is a channel amplifier down switch, and 9 is a D that converts the tuning digital signal output from the control circuit 1 into an analog signal tuning voltage.
/mu converter, 10i! 11 is a tuner, and 12 is a band switching circuit for latching node information.

In the above configuration, when the power switch SW1 is closed during channel presetting, the channel number is initialized and the channel number 1 is displayed on the display device 7 by a signal from the control circuit 1. To preset the desired reception chance, first set the write mode using the write/read switching circuit 2, and select the desired band (VHF4 or [U
HF). In this case, write/read switching circuit 2.
The band changeover switch circuit 3 has a key matrix configuration, and for example, the band changeover switch circuit 3 has a VHF
The band is equipped with a UHF key and a UHF key, and the band is selected by closing either one. By operating this band changeover switch circuit 3, the output σ from the control circuit 1 is encoded σ.
The received 2-bit band information is launched in the band switching circuit 12, and the tuner 11 is set to receive the channel of either band. On the other hand, at this time, a signal corresponding to the tuning digital signal How of the control circuit 1 is set.

Here, the manual tuning switch 4 is closed and an automatic sweep start command signal is supplied to start the automatic sweep operation, and the control circuit 1 outputs a tuning digital signal that changes every moment (rises from OV) to the D/MU converter. 9, and furthermore, a tuning voltage of an analog signal that changes every moment is applied to the tuner 11VC via the DC amplifier circuit 1o. When near tuning, the synchronizing signal detection circuit 6 detects the horizontal synchronizing signal 5Y)1G, its output changes from #L# to #H', and the control circuit 1 slows down its sweep speed. Then, at the optimal tuning point, the suppression of the manual tuning switch 4 is released, and the storage switch 5 is pressed to output a write command signal, thereby storing the digital channel information at that time at a predetermined address in the memory. Next, operate the channel up rumor down switch 8 to change the display on the display device 7 from 1 to 2, for example, and then close the manual tuning switch 4 again and perform the same operation to set the desired channel to each position. Can be preset. In addition, the tuning voltage U applied to the tuner 11vC
It will automatically change in the range of 0.5V to 30V.

After completing the channel preset for each position,
When the write/read switching circuit 2 is set to the read mode and the channel up/down switch 8 is operated, it becomes possible to receive an image of the previously preset desired channel.

However, in the channel selection device configured as described above, the band changeover switch circuit 3 is provided with a key for VHF and a key for UHF. When supplying to a broadcast area, one of the keys (
The problem arises that the operability is not good because the switch (switch) must be pressed down. In order to solve this problem, it is possible to keep one of the key switches closed, but the control circuit 1 receives other control signals (mode switching command signal from the write/read switching circuit 2, AFC information, memory (write command signal etc. of switch 5) is also input.
Therefore, if the key switch is kept closed, a problem arises in that other control signals cannot be detected and the key switch becomes inoperable.

OBJECTS OF THE INVENTION The present invention eliminates the above-mentioned drawbacks of the prior art.
Another object of the present invention is to provide a channel selection device that allows easy setting of reception bands for areas where only UHF broadcasting is available.

Structure of the Invention The channel selection device according to the present invention generates a band setting signal when the writing/reading switching circuit sets the mode to the writing mode, and uses this band setting signal to change the receiving band at the same time as switching to the writing mode. The band setting circuit is set to a certain band, for example, the VHF band, and if a detection output is generated from the synchronization signal detection circuit, the band setting circuit does not operate and the receiving band can be set by a switching operation. Once a channel preset has been performed, when resetting a channel, even if the write/read switching circuit is set to write mode, the synchronization signal detection circuit generates a detection output, so the band setting circuit does not operate and the synchronization The data of the channel selected in the read mode is output without returning to zero, and automatic sweep operation can be started from that point on, making it possible to perform channel preset operations efficiently. can.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. Figure 2 is a pronk diagram of the main parts of an embodiment of the present invention.
FIG. 3 shows detailed circuit configurations. In addition, in the figure, the same parts as in FIG. 1 are given the same numbers and will be explained.

In FIG. 2, reference numeral 13 denotes a pulse generating circuit, and when the write mode is set by the write/read switching circuit 2vC, for example, -24V is applied to the pulse generating circuit 13 to generate a pulse serving as a mode setting signal. Reference numeral 14 denotes a control drive circuit constituting a mode setting means, which is connected to the pulse generation circuit 1 described above.
When a pulse is supplied from 3, VHF band information or 1
It operates to supply TJHF information to the control circuit IK.

When the pulse is not supplied, the control circuit 14 does not supply band information to the control circuit 1. Therefore, when the write mode is set in the write/read switching circuit 2, a pulse is generated, VHF or UHF band information is added to the control circuit 1, the desired band is set, and the tuning voltage becomes zero vV.
c is set. From then on, as in the case of Fig. 1, press the manual tuning switch 4 to start automatic sweeping, slow down the sweep speed using the detection output of the synchronization signal detection circuit 6 when a TV signal is detected, and start manual sweeping at the optimal tuning point. By releasing the suppression of the tuning switch 4, closing the storage switch 6, and issuing a write command signal, the channel data at that time can be stored in the memory. In this way, after writing each channel data, if the mode is switched to the read mode, the channel data stored in the memory can be read out by operating the channel up/down switch 8, and the desired channel can be received. .

By the way, if you want to perform a channel preset again after completing the channel preset as described above, you can simply switch the mode to the write mode using the write/read switching circuit 2. When the pulse generation circuit 13 outputs a pulse and the control drive circuit 14 operates, and the band information is input to the control circuit 1, the tuning digital signal is set so that the tuning voltage becomes Ov. For example, when it is desired to preset the 10th channel, it is extremely inefficient to restart the sweep operation from OV and perform the preset operation.

Therefore, in this channel selection device, when switching to write mode again, it is assumed that the image of channel U6 is being viewed in the previous read mode. In view of the fact that the detection output can be obtained, the control drive circuit 14 is not activated by this detection output, so that the band information is not input to the control circuit 1. therefore,
The tuning digital signal output from the control circuit 1 is the data of the channel selected in the read mode, and the preset operation for the next channel can be performed efficiently. For example, if you are watching the 6th channel and want to preset the 10th channel at that position, according to this device, when switching to write mode, the tuning voltage of the 6th channel will be output, and therefore the next 10th channel will be preset. Channel presetting can be done easily in a short time.

Next, FIG. 3 will be explained. In Figure 3, 2a, 2
With the bid mode changeover switch, the state shown in the figure is the read state. C19R2 forms a differentiating circuit with a capacitor and a resistor that constitute the pulse generating circuit 13. The output terminal of the differentiating circuit is connected to the base of the transistor Q1 via the protective diode J+base resistor R3. The collector of transistor Q1 is grounded, and the emitter is connected to resistor R5.
Connected to power supply +VCC via. Further, the emitter of transistor Q1 is connected to the base of transistor Q2 via a pace resistor R6. The emitter of transistor Q2 is grounded through resistor R8, and the collector is connected to resistor R.
7 to the power supply +vcc and to the base of the transistor Q3. Transistor Q3
The emitter of transistor Qau is connected to the base of transistor Q4 via resistor R9, and the emitter of transistor Qau is connected to resistor R1.
[1] and is connected to the input port @ of the control circuit 1 via the diode D4. The collector of transistor Q4 is connected to output port Q or output port O via diode D2 or diode D5.

Here, when connected to the output port Q', a 2-pit digital signal corresponding to the VHF band is transmitted from the control circuit 1 to the output port O by turning on the transistor Q4.
If connected to , control circuit 1 is turned on by turning on transistor Q4.
[A digital signal indicating the UHF band is output.

This means that either one can be selected depending on the area. Furthermore, the base of the transistor Q1 [[ is connected to the common terminal of the mode changeover switch 2b via the resistor R1. The detection output signal of the synchronization signal detection circuit 6 is supplied to one fixed terminal of the mode changeover switch 2b, which is connected to the common terminal in the write mode.

Therefore, if the mode selector switches 2N and 2b are set to the opposite state to that shown in the figure, that is, to the write mode, in order to perform channel presetting, the differentiator circuit CI
+, R2VCU write voltage -24V is applied to generate a differential pulse. A negative pulse of this differential pulse is applied to the base of transistor Q1, the pace potential decreases, and transistor Q1 turns on. As a result, the transistor Q2 is turned off and the transistor Q5=Qa is turned on, so that, for example, VHF band information is input to the control circuit IK, and a signal indicating the VHF band is supplied to the control circuit 12VC.

On the other hand, when the channel preset is completed and is in the read state, for example, the 10th position is
If it is desired to re-record the channel data, the mode selector switches 21a and 2b may be switched to the write mode again. At this time, although a differential pulse is generated, since the fifth channel was previously selected, a detection output voltage is generated from the detection circuit 6 and applied to the base of the transistor Q1, and the base potential is pulled up. Q1 u cutoff, transistor Q2
is on, transistor Q3 is off, transistor Q
4 is turned off and no band information is applied to the input port @. Therefore, the tuning voltage is not returned to ovVc, the tuning voltage corresponding to the sixth channel is output σ, and the next tenth channel can be preset efficiently in a short time. .

In addition, in the above embodiment, the pulse generation is based on the write voltage -
24V is used, but this voltage is 10B voltage (+12V).
V) may also be used.

Effects of the Invention As described above, according to the present invention, by generating a mode setting signal and setting a reception band upon switching to the write mode, there is no need to perform a band selection operation again, and operability is improved. When switching from the reception channel playback state to the write mode again, by preventing the mode setting signal from being output σ at the detection output of the TV signal detection circuit, the reception channel can be tuned without the tuning voltage starting from Ov. Since the voltage is maintained, it has the advantage that the next channel can be reassembled very easily and efficiently.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional channel selection device. FIG. 2 is a block diagram of the main parts of a channel selection device according to an embodiment of the present invention, and FIG. 3 is a specific circuit diagram of FIG. 2.0 1...control circuit, 2...・Writing/reading switching circuit, 2a, 2b...Mode switching switch,
4...Manual tuning switch, 6...Memory switch, 6...TV signal detection circuit, 13
. . . Pulse generation circuit, 14 . . . Control drive circuit. Medical “〜ゞ′. Sleep 2nd figure Δ24v 5+-IJL c5

Claims (1)

[Claims] A storage device for storing channel data; a mode switching circuit for switching between a write mode for writing the channel information into the storage device and a read mode for reading out the channel data stored in the storage device; mode setting signal generating means for generating a mode setting signal when the mode setting signal is set to write mode; band setting means for setting the reception band of the tuner to one of the bands in response to the mode setting signal; and a television signal detection circuit. and means for preventing the mode setting signal generation means from outputting a mode setting signal based on the detection output of the television signal detection circuit when a television signal is detected.