Voltage controlled attenuator with no intermodulation distortion
US7256664B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 15, 2005 |
| Grant date | Aug 14, 2007 |
| Priority date | — |
| Expiry date | Oct 8, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01P1/227
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A preferred embodiment of the present invention comprises at least first and second thermistors, arranged into a classical Tee, Pi, or Bridged Tee attenuator design, a heating element, a temperature sensor, and a control circuit. The thermistors have different temperature coefficients of resistance and are in close proximity to the heating element and the temperature sensor. The control circuit receives a voltage signal from the temperature sensor, compares that signal with a voltage signal specifying a desired temperature, and applies electrical energy to the heating element until receiving a signal from the temperature sensor that the temperature of the thermistors matches the desired temperature. As a result, the attenuation of the attenuator can be changed at a controlled rate by varying the temperature of the thermistors, while the impedance of the attenuator remains within acceptable levels.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.