Keithley 194 Instruction Manual page 70

OPERATION
Table 3-10. Data For Mathematical Function
3.13.3 Peak
The peak mode allows you to display positive and negative
peak values in volts for the selected channel. Again, this
function is only usable for readings with two or more
SX"pleS.
Positive and negative peak values are defined as follows:
Positive Peak: the most positive sample stored in the
measurement buffer.
Negative Peak: the most negative sample stored in the
measurement buffer.
You can display positive and negative peak values as
f0110ws:
1. Press SHIFT PEAK (or PEAK if not in the data entry
mode). The instrument will then display the positive
peak value, as in this example:
1.2345 V PK+l
2. You can toggle the unit between the + PEAK and -PEAK
values by using the PEAK button. For example, the
negative peak value might be as follows:
-2.4451 V PK.1
Example:
From our example measurement in Table 3-10, we can easily
determine the positive and negative peak values. The mat
positive sample is number 3, which has an amplitude "f
14.25V. The most negative (least positive) sample is number
10, with a signal level of 1OV.
3.13.4 Peak-to-Peak
The peak-to-peak value of the selected channel can bc
displayed by pressing SHIFT PK T0 PK (or I'K T0 I'K ii
not in data entry mode). A typical display fw this nwdc
might be:
12.503 V P-P 2
In this case, the peak-to-peak value of the channel 2
measurement is being displayed.
Rx&to-peak values arc calculated as follwvs:
Where: VF.p = peak-to-peak value in v"lts
V+I, = most positive sample in the measurement
V-1, = most negative sample in the measurement
This function is valid for measurements of any size, but
when selected for a single-sample measurement, a reading
of zero will be displayed.
Example:
As an example, assume the instrument is displaying the
peak-to-peak value of the measurement shmvn m Table
3-10. The most positive sample is number 3, which has an
amplitude of 14.25V. The most negative sample has an
amplitude of lO.OV (number 10). Thus, the instrument
would calculate and display the peak-to-peak value as
follows:
Vp.p = 14.25 10.0
Vp.p = 4.25V
3. To cancel the peak mode, select another mathematical
function.
3-31