Wide band zero if quadrature demodulator using a intermediate frequency and a single local oscillator
US5761615A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 31, 1995 |
| Grant date | Jun 2, 1998 |
| Priority date | — |
| Expiry date | May 31, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/30
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A low power zero-IF selective call receiver has a local oscillator (106) that generates an injection signal for a first mixer (104) and a pair of quadrature phase related injection signals (122, 124) for a pair of second mixers (112, 114). The first mixer converts the received carrier signal (102) to an intermediate signal (108). A digital phase shifter/divider (116) coupled to the local oscillator (106) generates the pair of quadrature phase related injection signals (122, 124) at the frequency of the intermediate signal (108) which also equals the frequency of the local oscillator (106) divided by an integer greater then 1. The pair of second mixers (112, 114) coupled to the digital phase shifter/divider (116) converts the in and quadrature phase components (122, 124) of the intermediate signal (108) to respective in and quadrature phase baseband signals (126, 128).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.