Frequency modulated signal demodulator circuit and communication terminal equipment
US5703527A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 4, 1996 |
| Grant date | Dec 30, 1997 |
| Priority date | — |
| Expiry date | Apr 4, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03D3/007
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A frequency modulated signal demodulator circuit wherein an in-phase component (I) and an orthogonal component (Q) of a frequency modulated signal output from an orthogonal detector circuit are respectively delayed by one sampling time. The result (I.multidot.Qs) of multiplying the in-phase component (I) by a delayed orthogonal component (Qs) is subtracted from the result (Q.multidot.Is) of multiplying the orthogonal component (Q) by the delayed in-phase component (Is), and the subtraction result (d.theta.) is multiplied by an inverse (1/Ts) of the sampling time to derive an instantaneous angular frequency (d.theta./Ts), whereby the frequency modulated signal can be demodulated without any feedback loop which is required by conventional FM demodulator circuits, thus making it possible to avoid a deterioration demodulation characteristics due to the influence of phasing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.