Direct digital down conversion of a 10.8 MHz intermediate frequency signal in the personal handy phone system
US6134429A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 10, 1998 |
| Grant date | Oct 17, 2000 |
| Priority date | — |
| Expiry date | Apr 10, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/22
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A system for a direct digital down conversion of a 10.8 MHz intermediate frequency signal in the personal handy phone system. The present invention includes a system that enables a direct digital down conversion of a 10.8 MHz intermediate frequency signal into a digital baseband signal within cell stations and portable stations of the personal handy phone system. To perform this direct digital down conversion of a 10.8 MHz intermediate frequency signal, one embodiment of the present invention uses a hard limiter circuit, a sampler circuit and a digital down converter circuit. The hard limiter circuit of the present invention receives a 10.8 MHz intermediate frequency signal, utilized within cell stations and portable station of the personal handy phone system, and provides a threshold for it. The sampler circuit uses a 19.2 MHz oscillating clock signal to sample the intermediate frequency signal that is output from the hard limiter circuit. Due to spectral leakage, the 10.8 MHz intermediate frequency signal that was input into the sampler circuit is output as an 8.4 MHz intermediate frequency signal. The digital down converter circuit uses an 8.4 MHz signal to perform a digital dow…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.