User`s manual

Using Unsigned Data to Generate Waveforms
Transferring waveform segments as Digital-to-Analog Converter (DAC) Codes
to the AFG is faster than transferring a voltage list. This section shows how to
transfer the lists as DAC codes using the Unsigned number format. The DAC
codes are transferred to the AFG as a comma (“,”) separated list.
Note The AFG can only accept a single number format at a time. Thus, if the
AFG currently contains Unsigned data and you wish to send Signed data,
you MUST delete the data in memory first before enabling the AFG to
receive Signed data.
Using the Unsigned
Number Format
This section shows how to setup the AFG to receive DAC codes in the
Unsigned number format and how to generate the codes from voltage values.
Transferring DAC
Codes in the Unsigned
Number Format
With the AFG set to receive DAC codes in the UNSigned number format, it
receives the codes as unsigned or offset binary numbers. Use the
[SOURce:]ARBitrary:DAC:FORMat UNSigned command to select the format.
Determining DAC
Codes in the Unsigned
Number Format
For outputs into matched loads and with the amplitude set to maximum
(+5.11875V), the following DAC codes generate the following outputs:
Code 0 outputs -5.12 V or negative full scale voltage
Code +4096 outputs 0 V
Code +8191 outputs +5.11875 V or positive full scale voltage
To calculate DAC codes from voltage values, use the formula:
DAC Code = (voltage value / .00125) + 4096
For example, to output -2V:
DAC Code = (-2 / .00125) + 4096 = -1600 + 4096 = 2496
The UNS_DAT program shows how to store a waveform segment
(i.e., points of an arbitrary waveform) into the AFG’s segment memory.
The waveform segment is stored in the Unsigned number format. The data
is transferred to the AFG as a comma (“,”) separated list. The example
generates a 200 point +5 V to -5 V negative going ramp.
The commands are the same ones listed on page 226, except on how to
select the Unsigned format and how generate the data. These exceptions are
as follows:
Chapter 7 High Speed Operation 229