Profile: Crescent Frequency Products is a full service manufacturer of frequency control devices. We are an ISO 9001:2008 certified company. Our products include quartz based microprocessor crystals, clock oscillators, temperature compensated crystal oscillators (TCXOs), voltage controlled crystal oscillators (VCXOs), and oven controlled crystal oscillators (OCXO) in a wide variety of surface mount (SMD) and through-hole packages. Crystal oscillator is an electronic oscillator circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a very precise frequency. TCXO is a crystal oscillator that includes circuitry that compensates for temperature variations, to maintain a more constant frequency. A TCVCXO adds voltage control (VC) to one of the connection pads or pins as a means of fine tuning the frequency.