KR910000549Y1 - Channel display circuit - Google Patents

Abstract

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Description

Channel display circuit

1 is a circuit diagram of the present invention.

2 is an output waveform diagram of a timing pulse generator.

3 is a waveform diagram of each part of the present invention.

* Explanation of symbols for main parts of the drawings

1: Lifting pulse generator OP ₁ , OP ₂ : Comparator

2: differential pulse generator 3: timing pulse generator

4: On Screen Controller 5: Color Bar Driving Buffer

6: color bar driving unit

According to the present invention, in a voltage synthesis type remote TV, the band and channel number of a corresponding broadcast are respectively colored and bard so that a user can determine the channel number of the winning broadcast when searching for a channel or changing a channel. A channel display circuit for displaying on the screen as the position of.

In general, unlike a frequency synthesis method, a voltage synthesis method requires a user to search for a broadcast and store it in a nonvolatile memory device. In the conventional broadcast search method, three bands of a TV (VHF low band, VHF high band, UHF band) indicator lamp is equipped with simple functions such as flickering when searching for a broadcast and keeping it on after searching for a broadcast. Not only that, but the channel number of the broadcast could not be known when trying to change the channel even after multiple broadcasts were memorized.

In order to solve this drawback, the current voltage synthesis TV has three colors such as red, green, and blue superimposed on the screen to display broadcast bands by color and channel numbers by vertical lines. The color bar could be driven only when the channel was switched or when the power was turned on, but the RC time constant circuit for timing pulse generation to drive the color via was complicated, and a logic circuit was used to switch colors to the corresponding band. There was a cost increase factor.

Therefore, in view of the above problems, the present invention controls the on / off of the screen display by the timing generator for timing, broadcast switching, channel switching, power-on, memory input and fine tuning, and color conversion for color switching. The color bar driver is simply configured so that the power supplied to the driver is directly supplied from the tuner tuning voltage, so that the number and band of the corresponding television channel can be easily identified in the broadcast memory. The explanation is as follows.

FIG. 1 is a circuit diagram of the present invention. As shown in FIG. 1, reference is made using tuner tuning voltages VL, VB, and VU according to broadcasting bands (VHF low, VHF high, and UHF) of a television and using flyback heater pulp. The first comparator OP ₁ for comparing the voltage output from the reference pulse generator 1 for generating a pulse to generate a pulse signal whose duty ratio is varied according to the change in the tuning voltage, and the first comparator A differential pulse generator 2 for differentiating the signal output from OP ₁ ) and a second comparator for generating a sweep bar displaying the television channel number according to the tuning voltage by comparing the differential signal with the reference signal ( OP ₂ ) and low-timing timing signals for a predetermined time during adjustments such as broadcast search, broadcast channel memory, power-on, channel switching, and fine tuning. Output The timing pulse generator (3), but the operation to input the timing signal, upon adjustment of the above, the second comparator (OP ₂₎ and displays the output on the TV screen, during the normal operation and the second comparator An on-screen control unit 4 in which the output of OP ₂ is not displayed on the television screen, a buffer 5 for amplifying the output of the second comparator OP ₂ during the adjustment, and the buffer 5 described above. The output of) is input and the tuner tuning voltages (V _L , V _H , V _U ) are selectively supplied according to the frequency band of the television. The red, green or blue signal is superimposed on the sweep bar during the above adjustment. In this case, the television broadcasting band is constituted by the color via driver 6 which identifies the color as a color.

Here, a reference pulse generating unit (1) is operating in the condenser (C1) and the resistor transistor (Q1), a transistor (Q ₁₎ operated by (R1, R2) and differential pulse for differentiating the flyback heater pulse It consists of a resistor (R ₃ ) and a capacitor (C ₂ ) that generate a time-integrated waveform and provide it to the inverting input terminal of the comparator (OP ₁ ).

On the other hand, according to the frequency band of television broadcasting, the tuner tuning voltages are divided by the resistors R ₁₂ and R ₁₃ and input to the non-inverting terminal of the comparator OP ₂ . Here, the tuner tuning voltage is regarded as being inputted in 12 steps from the VHF low channel to the UHF channel.

The comparator OP ₁ compares these input signals, generates a pulse signal having a variable duty ratio, and applies it to the differential pulse generator 2 composed of the capacitor C ₃ and the resistors R ₄ and R ₅ . The differential pulse generator 2 applies the differential signal to the comparator OP ₂ , and the comparator OP ₂ generates a sweep bar that displays a television channel number according to the tuning voltage. The reference voltage setting resistors R ₁₇ and R ₁₈ are connected to the non-inverting input terminal of the comparator OP ₂ .

The timing pulse generator 3 may receive an input from a key of a remote controller (not shown) or may receive an input from a key attached to the television itself.

The on-screen control unit 4 is composed of a switching transistor Q ₂ for selectively muting the output of the comparator OP ₂ by operating by a signal output from the timing pulse generator 3, and a color bar driving butter. 5 is composed of a transistor (Q ₃₎ and a capacitor (C ₄₎ for amplifying the current output of the comparator (OP ₂₎ connected to the output terminal of the comparator (OP _2).

The color bar driver 7 receives the respective tuning voltages V _L , V _H or V _U and superimposes a red, green or blue signal on the sweep bar so that the current water band is VHF low (2-6 channels). ), VHF high (7-11 channels) or UHF (12, 13 channels) bands, with transistors (Q ₁ -Q ₆ ), diodes (D ₁ -D ₃ ) and resistors (R ₆ -R _11). It is composed of In the first diagram, R ₁₄ , R ₁₅ , and R ₁₆ are pull-up resistors for the output terminals of the comparators OP ₁ and OP ₂ and the timing pulse generator 3.

Referring to the operation of the present invention configured as described above is as follows.

First, when a flyback heater pulse (FIG. 3a) is applied to the reference pulse generator 1, the heater pulse is differentiated by the capacitor C ₁ and the resistors R ₁ and R ₂ so that the transistor Q ₁ is applied. The pulse applied to the base of the transistor Q ₁ is inverted through its collector and then integrated by the resistor R ₃ and the capacitor C _{3 as} supplied to the base of. Accordingly, the waveform generated and integrated in the reference pulse generator ₁ is applied to the inverting input terminal of the comparator OP ₁ as shown in FIG. 3B.

On the other hand, the tuner tuning voltage according to the broadcasting frequency band is divided by the resistors R ₁₂ and R ₁₃ and applied to the non-inverting input terminal of the comparator OP ₁ , and the tuning voltage is applied to the VHF low band, the VHF high band, and the like. It is set differently according to the UHF band. In other words, the tuner tuning voltage of the television broadcast channel is the highest when channel 2 is the lowest when channel 2 is the lowest.

At this time, the comparator OP ₁ compares the tuner tuning voltage inputted to the inverting input terminal with the tuner tuning voltage inputted to the non-rescue input terminal, so that only when the tuning voltage is higher than the reference pulse voltage, as shown in FIG. Generate a pulse. Accordingly, the output of the comparator OP ₁ has a shorter pulse width as the tuning voltage is lower, and the pulse width is longer as the tuning voltage is higher. In other words, a duty-variable pulse having the shortest pulse width in channel ″ 2 ″ and the longest pulse width in channel ″ 13 ″ is obtained, where the frequency is fixed at the horizontal frequency fV _H of the television. .

The 3c the output waveform of the comparator (OP _1), such as to help the condenser in ㉠ point as claim 3d help (C ₃₎ is by the difference in partial pressure due to the output voltage and the resistance (R ₄₎ (R ₅₎ of the comparator (OP ₁₎ At the zero point, the output of the comparator OP ₁ drops to 0 V, and discharge starts. At the zero point, the impedance of the capacitor C ₃ and the comparator OP ₁ and the time constants of the resistor R ₅ are discharged. By the end of the discharge, the partial pressure of the resistors R ₄ and R ₅ is converted into differential waveforms in the form of being applied and applied to the inverting input terminal of the comparator OP ₂ .

On the other hand, the non-inverting input terminal of the comparator (OP ₂₎ resistors (R ₁₇₎ a reference voltage divided by (R ₁₈₎ is applied, the resistance of the partial pressure ratio of the resistor (R ₁₇₎ and (R ₁₈₎ (R ₄ ) and if set equal to the partial pressure ratio of (R ₅₎ it is obtained as the 3e help waveform to the output terminal of the comparator (OP _2). That is, the high pulse of 12V is output only during the period in which the input of the inverting input terminal of the comparator OP ₂ is lower than the reference voltage of the non-inverting input terminal. Therefore, when the capacitance value of the capacitor C ₃ , which determines the discharge time constant of the differential pulse generator 2, and the internal impedance and resistance R ₅ of the comparator OP ₁ are adjusted, the output waveform of the comparator OP ₂ is adjusted. Since the following periods will be different, the thickness of the caravaa displayed on the screen is adjusted. In addition, the output of the comparator OP ₂ changes depending on the tuning voltage during the scanning period. Therefore, when the tuning voltage is low, a high voltage is output from the starting point between the syringes, and a sweep bar appears on the left side of the screen. On the contrary, when the tuning voltage is high, the high bar is outputted at the completion point between the syringes, and the sweep bar appears on the right side, so the position of the sweep bar is changed according to the tuning voltage.

In other words, for channel ″ 2-6 ″, which is a VHF low channel, the signal for channel ″ 2 ″ is displayed on the left side of the screen, and when channel ″ 3 ″ is selected, the sweep bar is shifted slightly to the right of channel ″ 2 ″. The channel ″ 4 ″ is shifted and displayed to the right of the channel ″ 3 ″. As such, the sweep bar from the VHF low channel to the UHF channel is sequentially moved to the left side of the screen sequentially to the right, so that the user can easily identify how many times the channel is present.

In this way, since the sweep bar signal is generated by the comparator OP _{2 while} the TV is turned on, as shown in FIG. 2, that is, when searching for a broadcast (Figure 2a), when inputting a memory (Figure 2b), The on-screen control unit 4 of the timing pulse generator 3 is configured to display the sweep bar on the screen during application (Fig. 2c), channel switching (Fig. 2d), and fine tuning (Fig. 2e). The output of the comparator OP ₂ is turned on / off.

That is, since the output of the timing pulse generator 3 is normally maintained high, the transistor Q ₂ configured inside the on-screen controller 4 is turned on. Therefore, since the output of the comparator OP ₂ is grounded in the case of the collector emitter of the transistor Q ₂ , the sweep bar is not displayed on the screen.

That is, since the output of the timing pulse generator 3 is normally maintained high, the transistor Q ₂ configured inside the on-screen controller 4 is turned on. Therefore, since the output of the comparator OP ₂ is grounded in the case of the collector emitter of the transistor Q ₂ , the sweep bar is not displayed on the screen.

However, when the color bars are to be displayed on the screen, the key inputs (ⓐ, ⓑ, ⓒ, ⓓ, ⓔ) shown in FIGS. 2A to 2C are input to the input terminal I of the timing pulse generator 3, respectively. Each of them is applied, and low outputs (ⓕ, ⓖ, ⓗ, ⓘ, ⓙ) are generated at the output terminal 0 of the timing generator 3, respectively. Therefore, since the transistor Q ₂ configured inside the on-screen control unit 4 is turned off, the output of the comparator OP ₂ is applied to the buffer 5. At this time, the buffer 5 forms and inputs an input signal to the color bar driver 6.

The signal input to the color bar driver ₆ is simultaneously applied to the transistors Q ₁ -Q ₆ through the resistors R ₆ ... R ₈ . Thus, transistors Q ₄ -Q ₆ operate only upon application of their collector bias voltages V _L (V _H ) (V _U ). Here, the band selector switching voltages of the tuners were respectively connected to the collector bias voltages V _L (V _H ) (V _U ) of the transistors Q ₄ -Q ₆ .

Therefore, when only the switching voltage corresponding to the band of the corresponding channel is supplied to only one of the transistors Q ₄ -Q ₆ , only the band display driver of the corresponding channel operates. For example, when receiving a channel in the VHF low band, if only a voltage is applied to V _L only by the tuner's switching voltage, only transistor (Q ₄ ) is ″ on ″ so the sweepbar signal is red via resistor (R ₉ ) and diode (D ₁ ). As applied to the base of the output transistor, the red output transistor drives the red cathode of the CRT to generate a red vertical bar on the screen. The VHF high band and the UHF band are operated as described above.

The present invention, which operates as described above, simplifies the circuit by variously and simply generating a timing pulse for driving color bars, and has a feature of reducing production cost by configuring a color bar driving unit that switches colors according to a corresponding band.

Claims (1)

In the reference pulse generator 1 generating the reference pulse using the tuner tuning voltages V _L , V _H , V _U according to the broadcast bands (VHF low, VHF high, UHF) of the television and the flyback heater pulses. The first comparator OP ₁ for generating a pulse signal whose duty ratio is variable according to the change of the tuning voltage by comparing the output voltages and the derivative for differentiating the signal output from the first comparator OP ₁ . The pulse generator 2 and the second comparator (OP ₂ ) for generating a sweep bar for displaying the television channel number according to the tuning voltage by comparing the differential signal with the reference signal and: broadcast search, broadcast channel memory, The timing pulse generator 3 which outputs a high state signal when watching a normal television when the timing signal in the low state is generated for a predetermined time during adjustment such as power-on, channel switching, and fine tuning. Timing signal But the input to the operation, so as to when adjustments of the displays the output of the second comparator (OP ₂₎ on a television screen, not at the time of the normal operation, the output of the second comparator (OP ₂₎ displayed on the TV screen The on-screen control unit 4 and: a buffer 5 for amplifying the output of the second comparator OP _{2 in} the above adjustment, and the output of the buffer 5 as an input and according to the frequency band of the television. Colorbar driver that receives the tuner tuning voltage (V _L , V _H , V _U ) selectively and superimposes the red, green or blue signal on the sweep bar to make the television broadcast band color by A channel display circuit, comprising (6).