Analog circuits

The functional blocks radios are assembled from.

Amplifiers and classes of operationGain, linearity and efficiency: classes A to C.OscillatorsAmplifier plus feedback: LC, crystal and VFO.FiltersLow-pass, high-pass, band-pass and notch; passive and active.Mixers and frequency conversionMaking sum and difference frequencies.Detectors and demodulatorsRecovering the audio from AM, FM and SSB.PLLs and frequency synthesizersLocking a variable oscillator to a stable reference.Power supplies and regulatorsTransformer, rectifier, filter, regulator; linear versus switching.Impedance matching networksL, Pi and T networks and how they transform impedance.Attenuators and padsReducing signal level without upsetting the impedance.