SELF-ACTUATING LOW-POWER RECEIVER FRONT-END PROTECTION CIRCUITYF
Original Publication Date: 1996-Nov-01
Included in the Prior Art Database: 2002-Apr-30
A system requires a small, low current, high per- formance VHF receiver to operate along side one or more high-power VHF or UHF transmitters. Because the receiver's antenna is physically close to the trans- mit antenna(s), the RF power that the receiver sees can be as high as 10 watts for as long as one minute. This amount of energy is enough to permanently damage the receiver's front end. The physical sepa- ration of the receiver's antenna and the transmit antenna(s) can't be increased. The operating fre- quency of the transmitter(s) can be the same as the receiver's operating frequency In many instances, the receiver will be powered "off' when a transmit- ter keys. The receiver and transmitter(s) are sepa- rate units with no interconnections. The transmit- ter(s) can't be modified to provide a "transmitter keyed" signal line. In summary, some means must be provided to protect the receiver's front end, even when the receiver is off, that is transmit frequency insensitive and has a minimal impact on the receiv- er'sperformance and size.