Tag Archives: RF Amplifier

Voltage Controlled Variable Gain Video Amplifier

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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… Read more »

Digitally Controlled High Frequency VGA

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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… Read more »

RF AGC with Digital Control

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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… Read more »

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

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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… Read more »

10W 2 Meters RF Power Amplifier

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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…. Read more »

Wideband RF Amplifier

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This is a circuit of Wideband RF amplifiers. This circuit use current-feedback components like the THS3202. The THS3202 was chosen because it has fast slew rate and wide bandwidth. The amplifier voltage gain of this circuit is 20 and stage voltage gain of this circuit is 10. Here is the… Read more »

LM359 1MHz Balanced Line Driver

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Balanced signal consist of two lines that have opposite phases, and should be received with differential input receiver. Balanced signal is employed in many telecommunication techniques to improve transmission system’s noise immunity. Balanced signal is usually transmitted in twisted pair cables. With twisted pair, the noise exposure is expected to… Read more »

Current Mmode 20MHz Noninverting Amplifier

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Current mode amplifier has the benefit of higher frequency operation, and LM359 comes as operational amplifier with this type op amplifier. Current mode (Norton) amplifier can be used in video, RF, of high speed communication design. You can apply this current mode noninverting amplifier in wide variety of applications, make… Read more »

Tuned Transistor RF Amplifier

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On the circuit below, the load resistor has been replace by a tuned circuit, C4 and L1. The tuned circuit is high impedance at resonance. The impedance is low at all other frequencies. Therefore, the signal which is amplified only at the resonance frequency. Since this type of amplifier is… Read more »