Category «RF and Video»

Remote Video System Multiplexer

Combination 8 channel multiplexer and amplifier (IC1) is the heart of the remote multiplexer box in the single coax video system. The MUX baseband video output is coupled by C11 to the coax and the video is decoupled by L1 from dc power arriving on the same line. All circuitry in the multiplexer box is …

Radio Frequency (RF) Watt Meter

For RF (radio frequency) transmitter experiment, watt meter is useful for optimizing the transmitter circuit. A simple RF watt meter circuit is shown in the  schematic diagram below. Because circuit is not frequency sensitive, calibration is accurate on all HF bands. The sensitivity is affected by meter movement, number of turns in primary coil, and …

10W 2 Meters RF Power Amplifier

When operating from 12.5 V auto battery, single TRW PT5757 transistor provides 10 W output. L1 is 4 tums No. 20 enamel and L2 is 10 tums No.20. Both, L1 and L2 has 3/32inch inner diameter. T1 is 4:1 transmission-line transformer made from 3-inch length of twisted-pair No. 20 enamel. This circuit can be used …

60-120MHz FM Receiver with AFC

We can say in simple words that AFC will lock the receiver to any valid RF signal. Below, we can see a basic block diagram of an receiver. The VCO is mixed with the RF signal which enter the mixer (yellow). The VCO can be a coil and a tunable capacitor. To bring out the …

TC9400 VFC for PLL FM Demodulation

FM demodulation can be done with phase locked loop (PLL), and this method is  common in high-end communication system. This system uses TC9400 that has high linearity. Using TC9400, the performance of phase-locked loop will increases greatly. That will give very precise tracking of Vout with respect to Fin. Here is the block diagram of …