Variable modulus interpolator, and a variable frequency synthesiser incorporating the variable modulus interpolator
US7006024B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 10, 2005 |
| Grant date | Feb 28, 2006 |
| Priority date | — |
| Expiry date | Jun 10, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/1976
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An indirect variable frequency synthesiser for synthesising selectable frequencies from a reference frequency including a multi-divisor programmable frequency divider located in a feedback loop of the frequency synthesiser for dividing the feedback frequency in the feedback loop, the divider being responsive to a varying control signal applied thereto representative of a rational number of selectable value for selecting the divisor thereof for fractional division of the feedback frequency. A variable modulus interpolator converts a fractional part of the rational number of selectable value to a varying digital code representative of the fractional part of the rational number. The variable modulus interpolator includes an Nth order sigma-delta modulator having N sigma-delta stages cascaded in MASH configuration, where N is an integer greater than one, and is responsive to a selectable value of a numerator and a selectable value of a denominator of the fractional part of the rational number for outputting the varying digital code. A primary summer sums a digital code representative of a selectable value of the integer of the rational number with the varying digital code from the vari…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.