Electronic low-pass filter circuit with an adjustable long time base
US4327335A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 19, 1979 |
| Grant date | Apr 27, 1982 |
| Priority date | — |
| Expiry date | Nov 19, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H17/00
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A filtering circuit having the behavior of a low-pass filter capable of having a long time constant. The filtering circuit comprises an input circuit for receiving a voltage input signal to be filtered. A summator circuit is provided for monitoring the input signal relative to an analog output signal from an accumulator circuit and providing an error signal representative of the difference of the input and output signals. The error signal is fed to a voltage controlled oscillator to generate a frequency signal proportional to the error signal. The accumulator has a frequency dividing circuit is provided to divide the frequency signal by a predetermined division factor to control the low cut-off frequency of the filtering circuit whereby to increase the response time thereof. The accumulator also integrates the divided frequency signal. An output circuit provides an output of the stored integrated frequency signal to constitute the analog output signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.