APPARATUS AND METHOD FOR LINEARIZATION OF CONTROL CODE-OSCILLATION FREQUENCY CHARACTERISTIC FOR MULTI-BAND DIGITALLY CONTROLLED OSCILLATORS AND APPARATUS CUSTOMIZATION FOR A FREQUENCY-LOCKED LOOP

摘要

The invention relates to an apparatus and a method for the linearization of the control code-oscillation frequency characteristic for digitally controlled oscillators. According to the invention, the apparatus comprises: a digital frequency converter (23), a control algorithm (27) and a block (29) for linearization of the control code - oscillation frequency characteristic of a digitally controlled oscillator (20), where the mentioned block (29) may have multiple operation modes, namely: a calibration or activation mode and an ordinary operation mode, where the operation mode may be selected by a calibration or activation block (44) by controlling a multiplexer (42). In the calibration operation mode, the multiplexer (42) activates a signal path (43), all the control code values being successively applied on said signal depending on the minimum distance of the counting base, which may be performed with an accumulator (31) consisting of a register (36) and an adder circuit (35) and a constant (34) which maintains the minimum distance of the counting base, for each control code applied, the value for the signal provided by the frequency converter (23) and the value of the control code (41) being memorized in a table (38), the so-obtained table (38) reflecting the control code - frequency characteristic of the oscillator (20), and after setting the characteristic, a sorting core (39) arranges the content of the table (38) in the ascending order of the memorized frequencies and stores the result in a second table (40). In the ordinary operation mode, the calibration/activation unit (44) controls the multiplexer (42) to select a signal (45) coming from the second table (40).