KR890007343Y1 - Modulation circuit of multiples transmitting signal - Google Patents

Abstract

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Description

Multiple Transmission Signal Modulation Circuit

1 is a block diagram of the present invention.

2 is a detailed circuit diagram of the present invention.

3 is a waveform diagram of an output signal in the main part of FIG. 2;

* Explanation of symbols for main parts of the drawings

10: first low pass filter 20: first comparator

30: second low pass filter 40: second comparator

50: synthesizer 60: modulated signal generator

70: first sawtooth signal generator 80: second sawtooth signal generator

The present invention relates to a multi-transmission signal modulation circuit, and in particular, in a short-range image transmission system, multiple channel image information is modulated to be transmitted through one transmission path by using pulse interval and width modulation (PIWM). To provide a circuit.

In the related art, since an image signal output through one channel is transmitted through a PWM (Pulse Width Modulation) circuit, there is a problem in that a PWM circuit and a transmission line according to each channel are connected to each channel.

Accordingly, an object of the present invention is to solve the above problems, and to provide a modulation circuit for transmitting each image signal to be transmitted through two channels in a PIWM method through one transmission path.

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

FIG. 1 is a block diagram of the present invention, wherein the first low pass filter 10 applying the image signal of the first channel is a band limiting circuit for low pass filtering, and the first comparator 20 is the first low pass filter 10. Is a circuit for level-correcting and sampling the output signal of the < RTI ID = 0.0 >), < / RTI > The pass filter 30 is a circuit for level-correcting and sampling the output signal.

The synthesizer 50 is a circuit for combining the output signal of the first comparator 20 and the second comparator 40, and the modulation signal generator 60 is connected to the signal output from the combiner 50. The first sawtooth wave signal generator 70 is a sawtooth wave for sampling by applying a signal output from the modulated signal generator 60 to be transmitted. A circuit for outputting a signal and applying it to the first comparator 20, a circuit for outputting a second sawtooth signal and applying it to the first comparator 20, and the second sawtooth signal generator 80 is a modulation signal generator 60 Is a circuit for outputting a sawtooth wave signal for sampling that applies an inverted signal of the transmission signal output from the second signal to the second comparator 20.

Detailed circuit diagram of the present invention configured as described above is shown in FIG.

In FIG. 2, the image signal a of the first channel is low pass filtered by the resistor R ₁ and the grounded capacitor C ₁ and then level corrected by the resistor R ₂ and the variable resistor R ₃ . Then, it is applied to the inverting terminal of the operational amplifier OP ₁ for sampling, and the image signal b of the second channel is low-pass filtered by the resistor R ₅ and the grounded capacitor C ₃ and then the resistor R ₆₎ and is the level adjusted by the variable resistor (R ₇₎ is applied to the inverting terminal of the sampling acceptable image of the amplifier (OP _2), each image signal that is output is sampled by the one operational amplifier (OP _1, OP ₂₎ is The OR is performed by the OR gate G ₁ and applied to the synchronization terminal of the flip-flop FF for signal modulation.

Since the power of logic " 1 " (high level) is applied to both input terminals of the flip-flop FF, a multiple modulated signal is output and transmitted from the output terminal Q of the flip-flop FF. Is applied to the gate of the transistor Q ₁ through one end between the transistor Q ₂ and the capacitor C ₂ applying the power supply Vcc via the NAND gate G ₂ , and the transistor Q ₁ is The sawtooth signal generated by the conduction is connected to be applied to the non-inverting terminal of the operational amplifier OP ₁ for sampling.

Then, the output terminal of the flip-flop (FF) ( ) Is an inverted signal of the image signal which is multimodulated and transmitted. The signal is connected to one end between a transistor (Q ₄ ) and a capacitor (C ₄ ) applying a power supply (Vcc) through a NAND gate (G ₃ ). It is applied to the gate of the transistor Q ₃ through, and the sawtooth signal generated as the transistor Q ₃ is conducted is connected to be applied to the non-inverting terminal of the operational amplifier OP ₂ for sampling.

3 is a signal waveform diagram in the main part of the present invention, which will be described in parallel with the circuit operation.

The third image signal of the first channel (a) is band-limited by low pass filtering by the resistor R ₁ and the grounded capacitor C ₁ , and the filtered first channel video signal is variable with the resistor R ₂ . The DC level is corrected by the resistor R ₃ and input to the inverting terminal of the operational amplifier OP ₁ .

On the other hand, as shown in the video signal of the second channel 3 (b), the low pass filtering and the DC level are corrected like the video signal of the first channel, and are input to the inverting terminal of the operational amplifier OP ₂ .

The non-inverting terminals of each of the operational amplifiers OP ₁ and OP ₂ have an output terminal Q, of a flip-flop FF. The input signal of the operational amplifiers OP ₁ and OP ₂ is a sampled signal as input to the sawtooth signal generated through the sawtooth signal generator interlocked with Appears.

That is, turning the output pulse claim 3 (f) of the output pulse claim 3 (e) help the operational amplifier (OP ₂₎ of the operational amplifier (OP ₁₎ it is a logical OR by the Iowa gate (G ₁₎ and synchronizes the flip-flop (FF) .

At this time, the flip-flop (FF) is inverted in synchronization with the negative edge (Negative Edge) of the pulse input to the synchronization terminal, each output terminal (Q, When the signal is a logic "1" and a logic "0" (low level) signal, as the flip-flop (FF) is synchronized, (Q, ) Is inverted into a logic " 0 " signal and a logic " 1 " signal.

Therefore, each output terminal Q, of the flip-flop FF, ) Are modulated waveforms as shown in FIG. 3 (g) and FIG. 3 (h), respectively.

As described above, the period represented by the logic " 1 " signal in the signal third (g) output from the output terminal Q of the flip-flop FF represents the information of the first channel video signal. If the sample point size of the information of the video signal is large, the logic "1" period of the flip-flop (FF) output signal is long, and if the sample point size is small, the logic "1" period of the output signal is shortened.

Then, the output terminal of the flip-flop (FF) In Fig. 3 (h) output from the signal), the period represented by the logic " 1 " signal represents information of the second channel video signal.

Therefore, the output terminal Q, of the flip-flop FF, Signal is a signal inverted from each other, so that the second channel video signal appearing in the period (3) of the output terminal (Q) of the flip-flop (FF), which is represented by the information of the first channel video signal, or in a logic "0" state. The information is multiplexed and output.

The first sawtooth signal generator 70 generates the sawtooth wave signal only when the signal is in the logic "1" state in the signal third (g) output from the output terminal Q of the flip-flop FF. OP ₁ ) is applied to the non-inverting terminal. Since the logic " 1 " preference is inverted and output to the logic " 0 " signal by the NAND gate G ₂ , the transistor Q ₂ to which the power supply Vcc is conducted is turned on. through the capacitor (C ₂₎ of the transistor (Q ₁₎ by the discharge voltage momentarily generated in the capacitor (C ₂₎ is not in accordance with the transistor (Q ₂₎ not conduct the release of the charge is the conduction is generated sawtooth signal.

On the other hand, the output terminal of the flip-flop (FF) As shown in the above, only when the signal 3 (h) is in the logic "1" state, the sawtooth wave signal is generated by the second sawtooth signal generator 80 and applied to the non-inverting terminal of the operational amplifier OP _{2 as} described above. .

Therefore, the sawtooth signal input from each non-inverting terminal of the operational amplifiers OP ₁ and OP ₂ for sampling is used to sample the video signal of each channel input to each inverting terminal.

In this operation, the information of the first channel video signal is loaded in the period (3) of the output terminal (Q) of the flip-flop (FF) or in the logic " 1 " state, and in the period in the logic " 0 " state. Since the information of the channel video signal is loaded, the video signal of the first channel is multiplexed by the second channel video signal PIM (Pulse Interval Modulation) by the PWM method and transmitted through the transmission path.

As described above, according to the present invention, since a video signal of two channels can be transmitted through only one transmission path, the circuit configuration of the transmitter can be simplified, and the power consumption can be reduced.

Claims (1)

A transmission system for transmitting an image signal through a transmission path, comprising: a first low pass filter (10) for applying low frequency filtering by applying an image signal (a) of a first channel, and the first region pass filter described above A second low pass filter which is band-limited by applying low pass filtering by applying the first comparator 20 to generate a sampled pulse signal after correcting the output signal of (10) and generating a sampled pulse signal. (30), a second comparator (40) for generating a pulse signal sampled after DC level correction of the output signal of the second low pass filter (30), and the first low pass filter (10); A synthesizing unit 50 for logically summing and outputting the output signal of the second low pass filter 20, and the first channel image signal is a signal having a logic " 1 " state in synchronization with the output signal of the synthesizing unit 50. The second channel image signal is modulated by multiplexing and modulating a signal of a logic " 0 " state, and the A first sawtooth signal generator 70 for generating a sawtooth signal when the transmission signal generated by the modulation signal generator 60 is in a logic " 1 " state and transmitting it to a first comparator for sampling the first channel image signal; A second sawtooth wave which is applied to the second comparator to sample the second channel image signal by applying the inverted signal of the transmission signal generated by the modulation signal generator 60 to generate a sawtooth signal when the logic is " 1 " Multi-transmission signal modulated signal, characterized in that it comprises a signal generator (80).