Agilent Technologies E8257D PSG, E8267D PSG manual Press Mirror Table

Custom Arb Waveform Generator Working with Filters

Coefficient	Value
0	−0.000076
1	−0.001747
2	−0.005144
3	−0.004424
4	0.007745
5	0.029610

Coefficient	Value
6	0.043940
7	0.025852
8	−0.035667
9	−0.116753
10	−0.157348
11	−0.088484

Coefficient Value

120.123414

130.442748

140.767329

150.972149

7.Press Mirror Table.

In a windowed sinc function filter, the second half of the coefficients are identical to the first half, but in reverse order. The signal generator provides a mirror table function that automatically duplicates the existing coefficient values in the reverse order; coefficients 16 through 31 are automatically generated and the first of these coefficients (number 16) highlights, as shown in the following figure.

8.For this example, the desired OSR is 4, which is the default, so no action is necessary.

The Oversample Ratio (OSR) is the number of filter coefficients per symbol. Acceptable values range from 1 through 32; the maximum combination of symbols and oversampling ratio allowed by the FIR Values editor is 1024. Remember, however, that the instrument hardware is limited to 64 symbols for real- time waveform generation, and 512 symbols for arbitrary waveform generation. The number of symbols equals the number of coefficients divided by the oversample ratio.

Chpater 6 151