Abstract: In an oscillating apparatus, a detection unit detects a frequency offset between an input signal and a reference signal. A code generation unit specifies a relationship among a code having a predetermined number of bits, the frequency offset, and a voltage to be applied to a voltage-controlled oscillator by a DAC, in accordance with a frequency offset detection state of the detection unit. The code generation unit also generates a frequency offset correction code having a predetermined number of bits in accordance with the specified relationship. The DAC applies the voltage to the voltage-controlled oscillator, in accordance with the relationship described above and the code generated by the code generation unit. The voltage controlled oscillator outputs an oscillator signal having an oscillation frequency corresponding to the voltage applied by the DAC.

Abstract: A method for calibrating multi carriage-multi probe impedance tuners for synthesizing distinct, user defined impedances at a number of harmonic frequencies, employs two-port s-parameter characterization of the tuning sections on a pre-calibrated vector network analyzer at a pre-selected number of probe positions. All tuner probes are wideband and capable of creating high reflection factor at all harmonic frequencies considered. The data are saved in memory and all permutations of the s-parameters at all harmonic frequencies are generated. Subsequently the data are organized blocks based on reflection factor values fitting in a number of segments of the Smith chart; this allows accelerated numeric search through a pre-selection of data block depending on the target reflection factor chosen. The method can be used for two three and four probe tuners.