Analysis, Pass/fail testing, Nalysis – Teledyne LeCroy WaveRunner XI SERIES Operator’s Manual User Manual

Page 142

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W

AVE

R

UNNER

X

I

S

ERIES

142

WRXi-OM-E Rev C

7. Choose whether to

Truncate

1

or

Zero-fill

2

the trace display.

8. Touch

the

Suppress DC checkbox if you want to make the DC bin go to zero. Otherwise, leave it unchecked.

the

Window field, select a window type.

rime

3

from the pop-up menu.

9. Touch

inside

the

Output type field, and make a selection from the pop-up menu.

10. Touch inside

11. Touch inside the

Algorithm field and select either Least P

ANALYSIS

Pass/Fail Testing

Comparing Parameters

Each Pass/Fail input (

Qx) can compare a different parameter result to a user-defined limit (or statistical range)

under a different condition.

The conditions are represented by these comparison operators:

At the touch of a button, test results can also be compared to these standard statistical limits:

current mean
mean + 1 SD
mean + 3 SD

1

When the FFT transform size does not match the record length, you can truncate the record and perform an FFT on the shorter record. T

will increase the resolution bandwidth.

2

Zero-fill is useful wh

his

en the source data for the FFT comes from a math operation that shortens the record. This is commonly encountered in

plitudes are interpolated to fit

r discontinuity in the filled data.

to minimize the effect

east primes algorithm that computes FFTs on transform sizes having lengths that can be expressed as factors of

5, or 10. or Power

generally runs faster

than the least primes algorithm. The price that is paid is a record length that is not the same as the acquired signal. The power-of-two FFT
uses the first 2

N

points of the record. For example, if you acquire 500 points in your trace, the power-of-two FFT would only use the first 256

points.

filtering operations like enhanced resolution. The missing data points are replaced by data values, whose am
between the last data point and the first data point in the record. This guarantees that there is not a first-orde
Since the data at the end of the record is "filled" data, it is advisable to select a weighting window other than rectangular
of the fill on the resulting spectrum.

3

The default algorithm is a l

2

N

*5

K

. This is very compatible with the record lengths encountered in the oscilloscope, which are often multiples of 1, 2, 4,

of 2 The other choice is a power of two algorithm where the record lengths are in the form of 2

N

. The power of 2 algorithm

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