User's Manual Part 2

RVP8 User’s Manual
April 2003
TTY Nonvolatile Setups (draft)
3–6
RVP8> ~
IFD Burst/IF Inputs are: SWAPPED
RVP8> ~
IFD Burst/IF Inputs are: NORMAL
The selection remains in effect for the duration of the setup session, but then returns to
NORMAL upon exiting the TTY monitor. The “~” command is very handy because it allows
the Pb, Pr, and Ps plotting commands to easily run with one input or the other. Here are two
examples of how this might be useful.
S When checking the range alignment on a Klystron system, the Pb plot can not be
used in the usual way to center the Tx burst because a continuous-wave COHO
(rather than a burst pulse) is typically used as the phase reference in these
systems. However, if you swap the Burst and IF inputs, you can then use the Pb
command to view and center the received leakage of the Tx pulse, and thus locate
range zero.
S When setting up the AFC loop, you can use your RF signal generator to simulate
the transmitter’s frequency, and then run the loop with swapped RVP8/IFD
inputs. The AFC servo will then hunt and follow the siggen frequency supplied
via the receiver. You can then make step changes in that frequency to verify that
the loop responds properly.
Note that the same input swapping function is also available via the RVP8/IFD toggle switches.
However, those switches may be located far away from the operator’s terminal; hence, the
command interface is still a valuable addition. The “~” command can only be used with the new
Rev.D RVP8/IFD; the command is unimplemented, and will not even show up in the “Help” list,
when earlier receivers are connected.