Tag «RF Amplifier»

Voltage Controlled Variable Gain Video Amplifier

This is a video amplifier circuit featured with controllable variable gain.  The control is done by adjusting the voltage of grid inputs of two FETs, which are configured as programmable voltage divider. This circuit can generate dynamic linear range attenuation up to 100 dB. This circuit still give a linear attenuation even at f=10.7MHz.  You …

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 …

VHF-UHF Antenna Amplifier (Booster) 40-500MHz

This amplifier has VHF (very high frequency) and UHF (ultra high frequency) response, you can use it for receiver booster for example. Here is the schematic diagram of the circuit: The current consumption is very low, under 20 mA for 14V voltage supply.  Lower current consumption can be achieved if we use 10V power supply, …

RF AGC with Digital Control

The AGC is used in many system especially communications. This AGC  works at 50Mhz, and the output voltage is set by a digital signal that is needed by Self-calibrating systems such as automatic test equipment which requires the high frequency response. During calibration, the AGC output voltage will be calculated by test equipment to get …

Digitally Controlled High Frequency VGA

Variable-gain amplifiers (VGAs) can be used in may types of systems, such as radio receivers. In this system, the input signal voltage depends on an uncontrolled variable, such as distance to the transmitter. To ensure that the input signal amplitude matches the input voltage range of key components, such as ADCs and DACs, thereby maximizing …