Voltage Controlled Variable Gain Amplifier

This is a circuit of voltage controlled variable gain amplifier. This circuit uses 2N4391 that will provide a low Rds(on) less than 30 Ohm. This circuit also uses a tee attenuator, that will provide optimum dynamic linear range for attenuation. We can obtain the attenuation greater than 100dB at 10MHz by providing proper RF construction techniques. Here is the circuit […]

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FET Cascode Video Amplifier

This is a simpleĀ  FET Cascode Video Amplifier circuit. This circuit has some features, they are reduction of feedback to almost zero and very low input loading. Here is the circuit: This circuit uses 2N3823 because it has high Yfs and low capacitance. RL and load capacitance limits bandwidth of the amplifier. [Source: National Semiconductor Application Note]

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Twisted-Pair Video Cable Driver and Receiver

Twisted-pair wiring is a wiring technique that usually used for in-building data communication. Compared to conventional coaxial-cable, this technique offers substantial cost saving, for video transmission on the same medium. A differential driver is used to launching a baseband camera signal to twisted pair. Twisted pair exhibits a roll-off characteristic that need equalization to correct for. The differential driver and […]

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Gamma Correction Circuit

Transducers is used in video system to convert optical signal to electrical signal in the acquisition. In the display, transducer is used to convert electrical signal back to light. Transducers often have a transfer function (the ratio of signal in to light out) that is unacceptably nonlinear. The newer technology of video camera transducers (the improved versions of vidicon-like tubes […]

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Video Line Driver

LT1206 is suitable for driving multiple video cables since it has 60MHz bandwidth, 250mA output current capability, and low output impedance. Please keep in mind about unterminated line effect when driving multiple cables. A reflected wave would propagate back to the driver an cause a crosstalk to other lines since the driver output is non zero impedance. The schematic diagramĀ  […]

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Video Limiter

To avoid exceeding luminance reference level standard or to avoid exceeding the input range of digitizer (ADC), video signal is often needed to be limited. The simple way to do this is by hard limiting the signal in the positive direction (white peak clipping), but this method completely destroy all information contained in the clipped region. The better way to […]

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