Monolithic broadband phase shifting circuit for analog data signals
US5408192A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 12, 1993 |
| Grant date | Apr 18, 1995 |
| Priority date | — |
| Expiry date | Oct 12, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H11/22
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An accurate phase shifting circuit providing two analog signals having a 90-degree phase shift between them from a single sampled-data input without the need for components external to a monolithic integrated circuit. A combination of two discrete-time circuits achieves the required 90-degree phase relationship over a broad frequency region. Several sample-and-hold circuits and multiplexors are used to produce two discrete-time versions of the analog input signal. Subtracting that older sample from the most-recent sample yields a forward difference signal and adding the most recent and the older samples produces a forward average signal. The phase difference between any single-frequency component of the forward difference and forward average signals is always 90 degrees. A pair of matched filters serves to reconstruct the sampled analog waveforms and to remove unwanted high-frequency noise in the +90.degree. output signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.