User`s manual

54 Appendix
Iterative Generation w. Intermediate Space
Utilize DLY2_counter to separate con-secutive waveform
generations in itera-tive generation mode. In this demo,
the original standard sine wave is repeated several times
as specified in IC_counter, with intermedi-ate space
determined by DLY2_counter.
Piece-wise Generation
When the value specified in UC_counter is smaller than
the sample size of waveform, the waveform is generated
piece-wisely. The intermediate space between each
piece is determined by DLY2_counter. In this demo, the
UC_counter is set to 1/8 of the sample size of waveform.
Amplitude Modulated
When external D/A reference is used, applying sinusoidal
voltage reference will result in an amplitude modulated
(AM) waveform generation. Users can use one D/A chan-
nel to generate sine wave, loop it back to AOEXTREF_A/
B pin, and generate AM waveform by another D/A chan-
nel using external reference. All can be done in a single
D/A group.
Frequency Modulated
By feeding AFI0/AFI1 with PWM source, pulse train from
VCO, or any time-varying digital signal, DAQ/PXI-2500
SERIES is capable of generating frequency modulated
(FM) waveform. Since all four channels are synchronized
in a D/A group, precise quadrature waveform generation
is guarantied, provided the waveform are shifted 90-
degree for the other channel. Phase difference of any
degree can also be setup. Combined with external High-
speed programmable Digital I/O card, Phase-Shift-Keying
or Phase-Reversal-Keying can also be achieved.