LeCroy DDA 7 Zi series, Руководство оператора

Страница: 502 / 544

WavePro 7Zi
501
WP700Zi-OM-E-RevA
where:
phase error = distance from sample to level * slope * DSO samples per bit cell
Notes:
1. Distance is normalized (-7200 = -1 level, +7200 = +1 level)
2. Slope is (normalized codes/DSO sample) around the channel sample position
3. Multiplying by samples per bit cell normalizes for DSO sample rate: slope
(codes/DSO sample) is cut in half when sample rate doubles
codes/DSO sample * DSO sample/bit cell = codes/bit cell
The gain terms must be small enough so that the correction is mostly uncompleted within
the latency (STEERING_L FIR delay) of the control loop. Otherwise the loop will
be unstable.
The spacing and phase corrections are in fractions of a bit cell.
possible error
messages:
"PLL_PROP_GAIN must be >= 0 and <= 1e-8"
keyword: STATE
arguments:
<which state> 0 to STATES minus 1
<previous state from 0> 0 to STATES minus 1 (or 100, see below)
<expected sample level from 0> -1 to 1
<previous state from 1> 0 to STATES minus 1 (or 100, see below)
<expected sample level from 1> -1 to 1
required?:
yes
Notes:
1. The states are specified in NRZ (nonreturn to zero) format, that is 0 and 1 are the two
polarities of magnetization. On the head signal (the first sample of) a negative going pulse
begins a "0" polarity region on the media, and a positive going pulse begins a "1" polarity
region. "from 0" means the bit cell which is no longer part of the state was 0 polarity.
Consider the state 0011. If the preceding state was 0001 then the state 0011 was arrived at
along the "from 0" transition. Similarly if the preceding state was 1001 then the state 0011
was arrived at along the "from 1" transition.
2. At least one STATE specification must be seen or the parse is considered failed.
3. In some cases one (or both) of the transitions to a state may not be valid, that is, they are
disallowed due to encoding constraints. In such a case use the value 100 as the "previous
state from" for that transition, this is recognized as disallowing the transition. Any other
value outside of 0 to STATES minus one is declared a parse error. If both transitions to a
state are disallowed, the state cannot be arrived at; it is invalid. You need not specify invalid
states (states that cannot be arrived at). For proper operation you must specify every state
that can be arrived at.
4. The STATES keyword, specifying the number of states, must be seen before a STATE