Posts Tagged ‘rf modulator’



Simple 27 MHz Receiver

Thursday, February 7th, 2008

This is a simple RF receiver mainly for low-distance digital radio receiver application. The analog output of this circuit should be connected to a schmitt-trigger signal conditioning circuit with a proper value capacitor (from collector of T3). L1 for 27Mhz is about 10 turns, 6 mm diameter coil body Read More Source:http://jap.hu/electronic/sregrcvr.html Thank you. Related [...]

RF Preamplifier by 2N2219a , 2N4427 , 2N3553

Tuesday, January 15th, 2008

Input needs only several mWatts (e.g. BF900) -> 300 mWatts OUT. This schematic is a often used buffer. It’s easy to build, clean and cheap. When you want even more power, you can replace the 2N2219a by a 2N4427 or 2N3553. You can lower the output by adding a little resistor (10..47 Ohm 1/2W) in [...]

SYNTHESIZER BASICS by SP8793

Tuesday, January 8th, 2008

A Phase Locked Loop (PLL) consists of a Voltage Controlled Oscillator (VCO), the output frequency of which is monitored and controlled. An error voltage steers the VCO and brings it back onto the correct frequency. The error voltage is generated by a Phase Sensitive Detector (PSD) which compares the VCO frequency with a reference frequency. [...]