Arbitrary (User) Waveforms; Sequenced Waveforms; Figure 1-5A, Segment 1 - Sin (X)/X Waveform - Racal Instruments 3155 User Manual

Arbitrary (User)
Waveforms
Sequenced Wave-
forms
1-12 Overview
The arbitrary waveform memory is capable of storing one or more
user-defined waveforms. The 3155 is supplied with 1 Meg of wave-
form memory. There is no need to use the entire memory for only
one waveform since the memory can be divided into smaller seg-
ments. Different waveforms can be loaded and the instrument can
be programmed to output one segment at a time.
The 3155 utilizes DMA (Direct Memory Access) to speed data
transfer from the host computer to the instrument.
The sequence generator is a powerful tool that lets you link and loop
segments. As a simple example of a sequenced waveform, look at
Figures 1-5a through 1-5c. The waveforms shown in these figures
were placed in memory segments 1, 2 and 3, respectively. The se-
quence generator takes these three waveforms and links and loops
them in a predefined order to generate the waveform shown in Fig-
ure 1-5d.
The sequence is useful for generating long waveforms with repeated
sections like NTSE video. The repeated waveform is programmed
once and the repeater loops on this segment as many times as se-
lected. When in sequenced mode, there is no loss of time between
linked or looped segments.
Figure 1-5a, Segment 1 – Sin (x)/x Waveform
User Manual 3155