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Video Modulator Circuits
Video Modulator Circuits
The FM oscillator/modulator is a voltage-control led oscillator, which exhibits a nearly linear output frequency versus input voltage characteristic for a wide deviation. It provides a good FM source with a few inexpensive external parts
The VHF frequency is generated by a tuned Hartley oscillator circuit. Resistors R2, R3, and R4 bias the transistor, with tapped inductor LI and trimmer capacitor Cl forming the tank circuit. Adjusting Cl determines the frequency. Capacitor C2 provides positive feedback from the tank circuit to the emitter at Q1. Capacitor C4 provides an RF...
if the timer is triggered with a continuous pulse train in the monostable mode of operation, the charge time of the capacitor can be varied by changing the control voltage at pin 3
Two IC rf modulators convert a suitable baseband video and audio signal up to a low VHF modulated carrier-Channel2 through 6 in the U.S., and 1 through 3 in japan-the LM1889 and the LM2889. Both !Cs are identical regarding the rf modulation function, including pin outs, and can provide either of two rf carriers with de switch selection of the...
Because the transconductance of an operational transconductance amplifier is directly proportionai to /ABc. the amplification of a signal can be controlled easily. The output current is the product from transconductance X input voltage. The circuit is effective up to approximately 200kHz.
Adding a diode, a resistor, and a capacitor to the SAW (surface-acoustic-wave) oscillator allows you to use the oscillator in FSK (frequency-shift-keying) applications. Dl, Rl, and Cl form a simple diode switch in which Dl shunts Cl to ground. When the digital FSK input to Rl is low, Dl is off, and the small junction capacitance of Dl couples...
Because power MOSFETs offer high power gain at both audio and radio frequencies, they are useful in many areas of radio-circuit design. For rf applications, a MOSFET"s large safe operating area, V0 s vs ! 0, protects it against damage from reflected rf energy. As a modulator, a MOSFET"s transfer linearity aids fidelity. In the...
Switching diodes are used to fire the neon lamps when negative-peak modulation hits 50. 60, and 100%. To use the circuit, keep an eye on the lamps.
This application uses the timer connected for astable (free-running) operation, with a modulating signal again applied to the control voltage terminal.
In this application, the timer is connected in the monostable mode. The circuit is triggered with a continuous pulse train and the threshold voltage is modulated by the signal applied to the control voltage terminal at pin 5. This has the effect of modulating the pulse width as the control voltage varies.
When the carrier level is adequate to switch the cross-coupled pair of differential amplifiers, the moduÂ· lation signal, which has been applied to the gate, will be switched at the carrier rate, between the collector loads. When switching occurs, it will result in the modulation being multiplied by a symmetrical switching function. If the...
This simple diode modulator delivers excellent results when used for high percentage modulation at low signal levels. Constants are shown for a carrier frequency of about 10 MHz, but, with a suitable tank, the circuit will give good results at any frequency at which the diode approximates a good switch. To extend frequency above that for which...
Video modulator circuit
These are modulator circuits for modulation of video signals on a VHF/UHF carrier. The circuits require a 5 V power supply and few external components for the negative modulation mode. For positive modulation an external clamp circuit is required.
Audio/Video to UHF TV Signal Converter (Modulator)
This is the circuit diagram of audio/video modulator. The circuit will convert an audio and video signal into a UHF TV signal. It`s desired to connect a video signal originating from a camera or other video source to a normal TV set. The audio and video signal is converted into a UHF TV signal so that the signal can be received through the TV ante
audio-video modulator circuit
The circuit will convert an audio and video signal into a UHF TV signal. It`s desired to connect a video signal originating from a camera or other video source to a normal TV set. The audio and video signal is converted into a UHF TV signal so. This is schematic diagram of a video amplifier ci
LM2889 Lm2889 Tv Video Modulator - National Semiconductor
The LM231 LM331 family of voltage-to-frequency converters are ideally suited for use in simple low-cost circuits for Analog-to-digital conversion, precision frequency-to-voltage conversion, long-term integration, linear frequency modulation or demodulation, and many other functions. The output when used as a voltage-to-frequency converter is a pul
SI2171 Worldwide Hybrid TV Tuner With Analog Demodulator
TBA120U Sound I.F. Amplifier/demodulator For TV
TDA2549 TDA2549 I.F. Amplifier And Demodulator For Multistandard TV Receivers
The circuits incorporate two FM Demodulator TDA2555 systems to perform the Demodulator functions required in a dual sound Carrier TV system for demodulating the sound Carriers The difference between TDA2555 and TDA2557 is the number of stages of the Limiting Amplifier Eight TDA2555 or five (TDA2557) stage Limiting Amplifier Quadrature Demodulator
TDA2555 Dual Tv Sound Demodulator Circuits - Nxp Semiconductors
The TDA3567 is a monolithic integrated decoder for the NTSC colour Television standards. It combines all functions required for the demodulation of NTSC signals. Further more it contains a luminance Amplifier an RGB-matrix and Amplifier These Amplifiers supply output signals up to 5 V peak-to-peak (picture information) enabling direct drive of the
ATV Repeater System Exciter
A model RTX-70 exciter that was originally used in the Brookdale ATV Repeater System. This page describes some the design considerations and new features possible with this new exciter, and includes schematics of the circuits designed during the exciter`s development. The ATV exciter described here uses a pair of Hamtronics model TA451 2-watt...
amplifier, with bias at cutoff. Q5 acts much like a grid-leak detector. Without the subcarrier input, the demodulator cuts off and prevents signals from passing. Of course, the chroma signal must be at a low level. Otherwise, chroma might gate the demodulator on. Positive excursions of the reference subcarrier are strong enough to gate the demodul
VHF/UHF TV Modulator
Simple oscillator that generates a frequency in the VHF or UHF region. The oscillator is modulated with the video signal and the modulated carrier wave thus generated is fed into the TV set`s aerial input via a cable. Then all that remains to do is tune the TV to the correct frequency..
Small TV Modulator Using A Motorola MC1374
How can television modulator be small and simple like this? First, it uses integrated circuit, and the second, any TV modulator is nothing more than amplitude..
Video Mixer Circuits
Video Wall Circuits
TV Video Circuits
Photo Flash Circuits
Video Amplifier Circuits
Recording circuit of phone conversations using PC
This circuit is used to record telephone conversations on your landline telephone. All you will need is this small circuit and subscription of your PC. There are few times when we forget what we said or told us. So we need recording. Sometime, not many years ago, recording of this kind of conversation was done with a small tape recorder. The...
FM Micro-Transmitter Bug Surveillance Circuit
The transmitter we recommend to build is quite simple. It can even be built by a beginner. However, unlike the ease of construction and its small size, it is almost certain that it will impress you with its outstanding performance. Its autonomy is 12-15 hours, with a 9 volt battery and its range is from 100 to 300 meters depending on the...
Construction of 50Watt 8Ω two-way Hi-Fi Speakers
The presented speakers are distinguished for their small dimensions and their extraordinary sound. Our home space is often limited and prohibitive for large speakers. This limitation does not mean that we will stay without high Sound Quality. Its design is simple, low cost and is easy to construct. Speaker types are too many and are designed in...
GSM modem circuit with Wavecom WMOi3
Modems are devices that connect either remote devices to a computer, or two or more computers to each other. Their connection is usually wired. The GSM modem we present is wireless. It can connect two computers, a computer with the internet or even be the central unit for a data acquisition system. Generally the construction is a GSM phone...
1W UHF Linear Amplifier with BLW33
This circuit is an amplifier for small transmitters operating in the UHF band, specifically in the 450-800MHz range. The amplifier works in class A and we used the well-known Philips BLW33 transistor for its manufacture. The construction, although simple, can be said to be quite critical due to the high frequency singularity. To achieve this, a...
8W Amplifier with TDA2003 circuit
Many times a small amplifier is needed to meet the needs of small spaces. This amplifier can be either mono or stereo, with this circuitry you can comfortably drive two small speakers. To build the amplifier you do not need anything but a few materials and a small power supply. The power of the amplifier, although low power, will solve many...
FM Linear Amplifier 400mW
This amplifier is intended for amplifying low signals from oscillators in the FM band. It does not have frequency regulators with variable capacitors and coils, it has a wide range and moderate power capable of driving several linear amplifiers. The whole construction is based on the two low-power 2N4427 transistors, which are designed for the...
50 Watt Hi-Fi power amplifier circuit
SGS Thomson's integrated TDA7294 is a high-frequency acoustic power amplifier, with true high-precision specifications, suited for all relevant applications. Its main feature is much higher output power than is usual in amplifiers with similar distortion performance. According to its manufacturer, the output stage of this 15-pin integrated can...
RF Remote Control Switch Rx-Tx circuits
This circuit consists of a 2048 radio remote control transmitter and the corresponding wireless receiver with very high reception sensitivity and low consumption. The combination of the two above gives a high-reliability remote control, ideal for security systems, alarms, automation, etc. At home, in the car and elsewhere. Using the wireless...
Digital Signal Integrity
Interconnection and Timing of Digital Circuits
CMOS Circuits Tutorial
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