Smart Sequence Mode: 2SMn SM smart sequence mode
The SM command selects a smart sequence mode (n=2 for test tape mode or 3 for
frequency sweep mode) and puts the LA102 back under keyboard control. Note that the
LA102 cannot decide when it has received all of the tones or sweeps and the remote
computer should determine this (by reading the tape counter, by asking the user or by
waiting the correct length of time, for example).
Interpolate Smart Sequence Results: 2IN
IN interpolate Interpolation
The IN command interpolates the raw frequency response data measured by the 2SM
command, and also puts a dummy U segment into the left and/or right segment lists to
indicate that the frequency response data is valid for that channel (ie that samples were
taken). The
2IN command should always be used when discrete tones have been
measured by the smart test tape mode and is recommended after a sweep has been
measured in case any of the 256 frequency samples were missed.
If the raw data is not interpolated it is still possible to read it using
2S? or 2R?,U
commands and invalid samples will be returned with a level of -128dB. Note that a
frequency response graph of the raw data will only show the measured values, and in the
case of test tapes this may only be 10 points out of the full 256.
9.21 User Sweeps
User sweeps allow frequency sweeps to be run as test segments with any start and end
frequency (ie not restricted to the four existing ranges 20-20kHz, 10-30kHz, 30-8kHz, 30-
4kHz and 300-18kHz provided by the existing sweep segments). The disadvantage is that
the LA102 cannot sensibly interpret the results which must be read and processed
remotely and the procedure for doing this is rather complex.
Define User Sweep Segment: USs,f1,f2,d,l
s is a sweep segment letter (OPQRSU or X). f1, f2, d are start frequency code, end
frequency code, and duration per frequency, as for the SW command, and l is the
(integer) level to output the sweep at, in dB, relative to Test Level. This command does
not run the sweep, it merely defines parameters for a segment labelled ‘@’. To run it,
define a sequence containing the @ segment (using the DS command), and run it (using
SQ). The @ character is not transmitted, but is replaced by the character s in the FSK
header, so that the segment will be interpreted by the LA102 as a standard 1.5s, 5s or 20s
sweep.
It is the users responsibility to ensure that the sweep timing is correct. The LA102 will
assume the sweep to be a 20Hz to 20kHz sweep, and will display and print it as such, so
for a meaningful graph the sweep data must be read from the LA102 (using S?) and
processed remotely.
The start frequency must not be in the vicinity of the FSK frequencies (1650-1850Hz) as
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9. Remote Control
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