Tone receiver comprising a switch capacitor zero crossing detector
US5359652A · kind A · utility
8Cited by
10References
5Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 1, 1993 |
| Grant date | Oct 25, 1994 |
| Priority date | — |
| Expiry date | Mar 1, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/1563
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A zero crossing detector which compensates input offset voltage by switching connections between certain capacitors. A first capacitor connected in parallel with the comparator input, is charged to this offset value during one switching step. Part of this charge is transferred to an input series-connected capacitor during a next switching step. These steps are repeated at a high switching rate. Preferably, a voltage step source is applied to the first capacitor in that next step, and functions as a threshold during the comparison function. Once the threshold has been exceeded, the voltage step source is reversed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.