4.0 User Defined Sequences
User defined sequences Programmable sequences Setting up sequences Sequence number Source ID
The ten test sequences in LA101 Bank 0 are editable via the front panel, or remotely with
Lindos Lin4win software. All other sequences may be viewed, but cannot be edited unless
they are first copied into one of the user sequences (sequences 0-10 are held in RAM,
while the other sequences are held in EPROM). When new, or after reset (4), Bank 0
contains the Lindos default sequences. Many users find that these make good starting
points when designing their own sequences.
The Lindos sequence system is very flexible and easy to use. Each test segment is
allocated a letter, and a sequence is built by simply specifying the segment letters,
together with an (optional) number which specifies the level that the segment will run at.
A typical sequence is therefore around 10 characters long and easily entered from the
front panel using the up-down keys to cycle through the character set. It is also possible
to enter messages to be displayed when the sequence is run, or transmitted to the
measuring set via FSK (useful for source identification when testing lines and links).
A wide range of segments are provided (table 3.2, page 40) to perform all of the
measurements available from manual mode including level, noise, crosstalk, distortion,
wow and flutter, speed and phase. Extra measurements not available in manual mode
include frequency response (over different ranges) and maximum output level (MOL).
Various control segments allow channel and impedance selection, pauses and repetition of
segments or sequences.
Meter ballistics
Most sequences will be built from these Lindos test segments which the LA102
automatically responds to. However, it is also possible to construct a sequence of tone
bursts (section 4.16) and this has many uses: a sequence can be used to test the level
accuracy and ballistics of a meter, similar to the PPM test available on sequence 19;
tones can be defined with record response corrections for making a test tape or disc; audio
channel identification for video tapes using intermittent tones can be generated. It has
even been used to demonstrate DCC compression on Tomorrow’s World (a popular
science and technology programme on BBC TV) and to generate morse code messages to
identify communication channels via a satellite link into a war zone.
The sequence definition is entered into the LA101, where it is held in non-volatile
memory; the LA102 will automatically respond to the segment letters and levels which
are transmitted in the FSK header at the start of each segment without any programming.
Test sequences can be created to perform tests at different levels and it is possible to
perform the same test at up to 5 different levels (frequency sweeps at different levels can
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