9 Dec
2009
9 Dec
'09
7:34 p.m.
Al Kossow wrote:
There is no need to record every value if it is only a
binary signal, you
can store the delta time to the next transition.
With my current implementation, I take that one step further, and
process the delta T's within the hardware, to see if they fall in a
particular range, and then store this equivalent RAW MFM data in the
memory. And then transfer contents of memory (once bit aligned with the
sync word, also in hardware) via USB to the PC. I understand where
having the raw delta T's inside a PC/or something with more power, makes
sense.
This is the difference on
a logic analyzer between 'state' and 'timing' modes. In 'state'
mode, you
sample and save every signal at each event. In 'timing' mode, a high
resolution
clock is used to measure the durations of each signal.
My (limited) understanding was that timing mode you used a clock source
internal(ie local oscillator) to the logic analyzer to determine when to
sample --- it not synchronized with the DUT.
And state mode was an external clock, synchronized with the clock
present within the DUT, which told the LA when to sample. At least
that's how I understood it.
This is how I've used both my LAs...
Thanks
Keith