Digital filtering, data rate conversion and modem design
US5500874A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 28, 1994 |
| Grant date | Mar 19, 1996 |
| Priority date | — |
| Expiry date | Jan 28, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L7/0029
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A digital filter 23 receives a control signal which specifies what filter coefficient values should be used. The control signal can be changed repeatedly so as to dynamically select the coefficients in response to the value of a control parameter. The filter 23 can be configured as a data rate converting filter in which the control signal represents the current phase relationship between the input data stream and the output data stream. The phase control signal can be provided as the phase output of a numerically controlled oscillator 67 having an oscillation frequency which is a multiple of one of the data rates and which is clocked at a multiple of the frequency of the other data rate. The data rate converter can be used as part of a data modulator or demodulator, thereby allowing an analog-to-digital converter 19 or a digital-to-analog converter 143 of the modulator or demodulator to run at a fixed arbitrary frequency substantially regardless of the data rate of modulated symbols.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.