1- Maximum bandwidth of 3.2MHz 2- Input impedence of 75 ohms 3- Uses 300mA 4- R820T - Min freq (24) and max freq(1766) 5- An SDR simply works by receiving an analog radio signal and then using an ADC 6- In practise an ADC will work up to a certain frequency 7- RTL2832U is a type of ADC which works up to 28.8MHz 8- To digitalize higher frequency signals we need an IF mixer stage to convert all received frequencies down to the frequencies that the ADC can use which is the job of the tuner chip(R820T) 9- It uses I/Q samlpling where 2 ADCs are used 10- Poor crystal tolerances Pulse Code Modulation 1- It is a signal processing techique to digitally represent analog signals. 2- 8000Hz is the sampling rate of telephone and encrypted walkie-talkie and wireless microphone transmission and 44100 Hz for CD audios and 48000 Hz for DVDs. What is RF Gain ? Noise interferes with signals and it comes from the atmosphere, other nearby channels that overlap slightly, and environmental surroundings. To counteract noise, RF gain acts as a sensitivity filter. It reduces noise in the receiver without reducing reception power as a CB radio squelch does.