| 摘要 |
PCT No. PCT/FI96/00015 Sec. 371 Date Jul. 22, 1997 Sec. 102(e) Date Jul. 22, 1997 PCT Filed Jan. 5, 1996 PCT Pub. No. WO96/23366 PCT Pub. Date Aug. 1, 1996In the method and circuit for creating a modulated signal, one input signal of a phase comparator (509) of a phase-locked frequency synthesizer is an offset frequency (f2), which is created from an adjustable oscillator's (511) output signal (fTX) by mixing it with a mixer frequency (f1) and filtering the obtained result in a low pass filter (508). The other input signal is a fixed reference frequency (fr). The adjustable oscillator (511) is controlled with a control signal (VCMOD), which contains a component resulting from the phase difference of said input signals (fr, f2). Modulation is created in the output signal (fTX) of the loop by adding a frequency or phase change to at least one of the input signals (fr, f2) or their derivatives, advantageously with pulse delay technology. |
