Method and circuit for creating a modulated signal in a transceiver
US5991605A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 22, 1997 |
| Grant date | Nov 23, 1999 |
| Priority date | — |
| Expiry date | Jul 22, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/12
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
In 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 (f.sub.2), which is created from an adjustable oscillator's (511) output signal (f.sub.TX) by mixing it with a mixer frequency (f.sub.1) and filtering the obtained result in a low pass filter (508). The other input signal is a fixed reference frequency (f.sub.r). The adjustable oscillator (511) is controlled with a control signal (V.sub.CMOD), which contains a component resulting from the phase difference of said input signals (f.sub.r, f.sub.2). Modulation is created in the output signal (f.sub.TX) of the loop by adding a frequency or phase change to at least one of the input signals (f.sub.r, f.sub.2) or their derivatives, advantageously with pulse delay technology.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.