Heterodyne radio receiver with plural variable frequency local oscillator signals
Granted: February 25, 1997
Patent Number:
5606736
A satellite navigation receiver uses common dual-conversion superheterodyne and frequency synthesizer circuitry for receiving signals from both the GPS and the GLONASS satellite navigation systems. Successive first and second frequency down-converters in the receiver chain are fed by first and second local oscillator signals which are both variable in frequency such that the frequency of the first local oscillator signal is an integral multiple (preferably 8) of the second local…
Communication network signalling system link monitor and test unit
Granted: October 10, 1995
Patent Number:
5457729
A communication network signalling system couples a signal transfer point to a plurality of channel banks through links which include link monitor and test units. The link monitor and test units, which monitor the links in a passive, non-obtrusive manner and which at the same time are capable of being serially coupled into the link so as to insert signals in series with the link and to otherwise accomplish in-depth link testing and analysis, each include a pair of channel units coupled…
