USKI-5 Universal Sequencer & Keying Interface
© Copyright 2015 QSK, llc
www.qskllc.com
Page 14
TIMING EXAMPLES
Several examples of typical timing delays for USKI-5 Program (A), (B), and (C) are presented in
this section. These are only examples and actual timing required may be different depending on
the specific devices or station configuration.
USKI-5 Program (A)
For the station configured as in figure 2, the following timing delays may be a good starting point
with Program (A):
SEQUENCE TYPE (CW, PTT, etc.):____CW & PTT___for Program (A)_____________________________
DEVICE
TMA
XVTR
AMP
PTT INPUT TO
TX
CW INPUT TO
TX
OUTPUT #
1
2
3
4
5
START
DELAY, ms
0
15
0
15
See note 1
15
See note 2
END
DELAY, ms
0
0
5
0
See note 1
30
See note 2
Note 1: used only for PTT input and is skipped in the CW sequence
Note 2: used only for CW input and is skipped in the PTT sequence
Since the TMA must be protected from transmitter RF output, to be on the safe side, it is the first
device switched off or out of circuit. In this example it is assumed that there are mechanical
relays which do this switching and transition in 10 ms. In case the XVTR is capable of RF output
by itself, its transition to a transmitting mode is delayed by 15 ms to ensure that the TMA is off
line (if it is certain that the XVTR does not have output until driven on its transmitter input, start
delay
2
could be set to zero). With no additional delay, the amplifier is then keyed. Assuming the
amplifier requires 15 ms to be ready for transmission, that delay is applied to start delays
4
and
5
. In order to make up for time lost during the start sequence, the sum of start delays for CW
operation is applied to end delay
5
. To be sure that the end of the CW symbol is not truncated
and the transmitter has a 5 ms CW envelope decay time, this delay is applied to the amplifier
end time.
USKI-5 Program (B)
Programming for USKI-5 Program (B) is similar to Program (A) except there is provision for two
different sequences. Therefore two worksheets should be used, one for each mode.
