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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
Ultrasonic distance finder circuit
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is measured. There are three main categories of distance measurement methods in use: a) By...
Simple Metal detector circuit with CD4030
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to find something potentially valuable, hidden a few centimeters below the soil. So many...
Fully automatic watering circuit for flower pots
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This circuit comes as a solution to this problem. Depending on humidity of the pot at...
Simple deep searching metal detector circuit
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the circuit of this metal detector, it is possible to detect a metal coin in depth of 90 to...
Sub-Harmonic Bass Converter for Electric Guitars
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound, such as filtering or distortion. Instead, a frequency division system produces outputs...
Echo Depth Sounding Sonar for Boats
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the calibration of the rope. This arrangement still exists in some yachts. The big...
100W HiFi Audio Amplifier Circuit
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power supply must be symmetrical so that no electrolytic capacitors are needed at the outlet....
Plant-Pot Water Level Indicator Circuit
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower. The circuit of the device is shown in Figure 2. The water detection is made from the bottom...
Analogue Sound Preasure dB-Meter Circuit
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to have a good accuracy we will get the limits of 20Hz to 20KHz. A sound to be heard does...
DIY HV Variable Capacitor
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Digital Signal Integrity