Electromagnetic wave receiver
US4748688A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 28, 1986 |
| Grant date | May 31, 1988 |
| Priority date | — |
| Expiry date | Apr 28, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/1638
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A receiver includes a receiving circuit for receiving an electromagnetic carrier wave modulated by a message signal, a detector ciruit for separating the message signal from the carrier wave, and an output circuit. The detector circuit has a Q ratio sufficiently low that the detectable band width is more than twice the modulation frequency change. The detector output signal has a noise voltage level when no carrier is present that is higher than the voltage of the message signal with a carrier present. An output circuit senses the level of the detector output signal and passes signals with a voltage level below a predetermined level and otherwise blocks the output signal. The filtering of the output circuit is sufficiently low that its response time is faster than a tenth of a second. The output circuit includes a noisy input related to the detector output and a reference input. A pair of diodes connect the noisy input and the reference input enabling the reference input to track the noisy input to prevent false data outputs.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.