Posi Phase Diversity
The USR-100 receiver utilizes Telex’s patented Posi Phase auto
diversity circuit. Unlike other types of diversity which receive with
only one antenna at a time, Posi Phase utilizes both antennas at all
times. This results in a stronger signal from the microphone for
cleaner audio and greater range.
If the microphone signal begins to go out of phase (a common cause
of “drop outs” with other types of diversity) the Posi Phase circuit
adjusts the phase angle between the two antennas’ receiving circuits
to prevent phase cancellation. This action is indicated by the 0 and
180 degree diversity lights on the front panel
Antennas
There are two TNC type antenna connectors on the rear panel. These
connectors are superior to the more common BNC connectors, both
electrically and mechanically. TNC connectors are becoming the
standard of the industry due to their heavy use in the Cellular Phone
industry. Quarter wave antennas are supplied for normal use or an
optional antenna accessory kit can be used to rack mount the anten-
nas. Optional half wave antennas with coax can be used for remote
installations. Both antennas must be used as both are active at all
times, unlike other types of diversity that only use one antenna at a
time.
Computer Controlled Channels
The VCO (Voltage Controlled Oscillator), which is the heart of any
Phase Locked Loop Receiver, is controlled by an on-board PIC
microprocessor. Each individual USR-100 RF stage tuning element
is also under the direct control of the microprocessor. This directs the
receiver to undergo an “Automatic Self Tune” step each time the
channel is changed. This is unlike many receivers on the market that
simply have “wide band” designs that allow interference to enter the
most sensitive stages of a receiver to cause inter-modulation and
noise. Other items under processor control are the channel selection,
spacing and display, the AF and RF displays and diversity operations.
This marriage of digital precision with real analog sound provides
the user with the best of both technologies.
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