Oscillator frequency offsets

摘要

Methods and devices relating to radio applications. An input signal with an input frequency is fed into a double quadrature mixer circuit along with a local oscillator signal with a local oscillator frequency. These two signals are multiplied by the mixer circuit and produces an output signal with a frequency substantially equal to either a sum of the local oscillator frequency and the input frequency or a difference of the local oscillator frequency and the input frequency. By using the quadrature mixer, the output signal consists mainly of only one sideband of the multiplication process. The carrier is mainly suppressed along with the other sideband. The output signal is particularly useful as a small frequency offset for a synthesized signal.