Active high-power bandpass filter
US4257007A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 16, 1979 |
| Grant date | Mar 17, 1981 |
| Priority date | — |
| Expiry date | Apr 16, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H19/008
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An active power-line filter which provides bandpass filtering and transient uppression. The high-power signal to be filtered is modulated to form a chopped waveform within an envelope defined by the input waveform and the modulation is removed by passing the chopped signal through a low-pass filter. The output of the low-pass filter is then compared in a differential amplifier with a low-power reference signal which is phase-locked to the primary component of the high-power signal. The output of the differential amplifier is phase-compensated for the effects of the low-pass filter and is compared to the reference in a phase-detection multiplier to produce an error signal to adjust the duty cycle of the chopped waveform so that the waveform at the output of the low-pass filter is identical to the reference waveform. For periods when the high-power signal is out of phase with its primary component, the polarity of the high-powered signal is reversed at the input of the active filter to allow the filter to compensate for this situation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.