Atec Agilent-53200A Series - Manual (Page 19)

19
Resolution enhancement factor (R
E
)
The resolution enhancement (R
E
) calculates the added frequency resolution beyond the basic reciprocal measurement
capability that is achieved for a range of input signal frequencies and measurement gate times. The maximum enhance-
ment factor shown is for input signals where T
SS
> T
E
and is limited due to intrinsic measurement limitations. For signals
where T
SS
<< T
E
, R
E
may be significantly higher than the specified levels. R
E
will always be >=1.
For signals where T
SS
>> T
E
, R
E
= √(F
IN
* Gate/16) R
E
is limited by gate time as show below
Gate time > 1 s, R
E
max of 6
Gate time 100 ms, R
E
max of 4
Gate time 10 ms, R
E
max of 2
Gate time < 1 ms, R
E
= 1
Interpolation between listed gate times allowed.
Single shot timing (T
SS
)
Timing resolution of a start/stop measurement event.
Skew
Skew is the additional time error if two channels are used for a measurement. It is not used for width, rise/fall time, and
single channel time interval.
T
accuracy
For 5v (500µV 2 + E
N
2 +Vx 2 ) ½
SR
-TRIG POINT
For 50v (5000µV 2 + E
N
2 +Vx 2 ) ½
SR
-TRIG POINT
± T
LSE-start
± T
LSE-stop
± ½ V
H
- ½ V
H
SR
-start
SR
-stop
SR
-start
SR
-stop
T
accuracy
is the measurement error between two points in time.
Threshold error (T
E
)
Threshold error (T
E
) describes the input signal dependent random trigger uncer-
tainty or jitter. The total RMS noise voltage divided by the input signal slew rate
(V/s) at the trigger point gives the RMS time error for each threshold crossing.
For simplicity T
E
used in the Random Uncertainty calculations is the worst T
E
of all the edges used in the measurement. RSS of all edge’s T
E
is an acceptable
alternative. Vx is the cross talk from the other standard input channel. Typically
this is -60 dB. Vx = 0 on 53210A, and when no signal is applied to other stan-
dard input channel on 53220A/53230A. (Note: the best way to eliminate cross
talk is to remove the signal from the other channel).
Threshold level timing error (T
LTE
)
This time interval error results from trigger level setting errors and input hyster-
esis effects on the actual start and stop trigger points and results in a combined
time interval error. These errors are dependant on the input signal slew rate at
each trigger point.
V
H
= 20 mV hysteresis or 40 mV when Noise Reject is turned ON. Double V
H
values for frequencies > 100 MHz.
[ ]
53210A 53220A 53230A
R
E
1 use R
E
equation use R
E
equation
T
SS
100 ps 100 ps 20 ps
Skew 100 ps 50 ps
T
accuracy
200 ps 100 ps
Definition of Measurement Error Sources and Terms used in Calculations
Confidence Level (k)
For 99% Confidence use k= 2.5 in accuracy calculations.
For 95% Confidence use k= 2.0 in accuracy calculations.