Multi-phase trapezoidal wave synthesizer used in phase-to-frequency converter
US5943379A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 11, 1997 |
| Grant date | Aug 24, 1999 |
| Priority date | — |
| Expiry date | Jun 11, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/089
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A trapezoidal waveform synthesizer converts a digital phase error signal into a plurality of phase-separated trapezoidal analog waveforms. The trapezoidal waveform synthesizer includes an up/down counter that counts the positive and negative phase errors and generates a multi-bit, parallel digital counter output signal that indicates a cumulative current value of the phase errors. The counter output signal includes a least significant bit (LSB) portion and a most significant bit (MSB) portion. An upper PDM circuit converts the MSB portion of the output signal counter and a portion of the LSB portion of the counter output signal to a plurality of sets of serially-weighted multi-bit output signals. A lower PDM circuit converts the MSB and LSB portions of the counter output signal to a plurality of serially-weighted single-bit output signals. Each of the sets of multi-bit outputs and a corresponding one of the single-bit outputs are provided to an RC circuit that converts the digital signal to an analog voltage such that the waveform synthesizer provides a plurality of phase-separated trapezoidal waveforms.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.