I have a (very) low cost (Feeltech FY3224 AWG -as little as $45 now) and one can use CSV file to generate custom waveforms. You need to write out a CSV file containing one complete cycle of the wave form and then load it. This would be less convenient than what you might be able to dial up with a better AWG but really cheap, and still quite usable.
Also, it would be scriptable so would lend itself to all sorts of automation. The software it comes with is for PCs but it runs fine under Wine. Also, there are Python tools so it can be used under any platform natively. You speak to it via a USB UART adapter it has internally.
Using Python it seems you can also create waveforms on the fly- see below (have not done this yet myself, the text below is from the readme and help output for the command line tools)
So, that means you can loop through any arbitrary values in scripts.
I've also attached a file that contains the communications specification.
All this probably also applies to the newer version.
However, if you plan on getting one you really must read up on the Feeltech's shortcomings, specifically a major issue with its power supply and leakage voltage. (which is easy to work around)
Otherwise you could zap your devices under test. Basically you need to attach a good ground to it and make sure it stays attached. Thats a small price to pay though.
I've found the feeltech to be very useful.
--------------
Here is some info on the python-feeltech tools (development archive is on github):
python-feeltech$ cat README.md
# python-feeltech
Python library for controlling FeelTech FY32xx waveform generators
Install with
```
$ sudo pip3 install feeltech
```
## Library usage
To create FeelTech object
```
>>> import feeltech
>>> ft = feeltech.FeelTech("/dev/ttyUSB0")
>>> ft.type()
'FY3224S'
```
The two channels can then be accessed
```
>>> ft.channels()
[<feeltech.Channel object at 0x7f577b11fd10>, <feeltech.Channel object at 0x7f577b11fcd0>]
```
and to set various parameters
```
>>> c.frequency(30e3)
```
The calls can be chained like:
```
>>> c.frequency(30e3).amplitude(3.3)
```
Or even
```
>>> c.frequency(1e3).waveform(feeltech.SINE).sleep(3).waveform(feeltech.SQUARE)
```
To upload a waveform (decaying exponential):
```
>>> ft.upload_waveform(2, [int(e ** (-x / 1000) * 2 ** 12) for x in range(2048)])
>>> c.waveform(feeltech.ARB2)
```
## Commandline tool
```
$ fytool -h
usage: fytool [-h] [--port PORT] {type,set,sweep,frequency,counter,upload} ...
FeelTech FY32xx control utility
positional arguments:
{type,set,sweep,frequency,counter,upload}
type display the device type
set set channel properties
sweep Perform a frequency sweep
frequency Show frequency measured
counter Show counter value
upload upload arbitrary waveform
optional arguments:
-h, --help show this help message and exit
--port PORT, -p PORT serial por
```
To set channel 1 frequency to 1 MHz, waveform to triangle and amplitude to 1V:
```
$ fytool set -c 1 -f 1e6 -w triangle -a 1
```
Reading the internal frequency counter
```
$ fytool frequency
1000010
$ fytool counter
545269
```
To perform a loagrithmic sweep from 1 kHz to 10 kHz, with period of 1 second and lasting for total of 50 seconds:
```
fytool sweep -s 1e3 -e 10e3 --period 1 --time 50 --type log --waveform square
```
## TUI
There is also a curses interface to control the device
```
$ fytui /dev/ttyUSB0
```
There is a bunch of keyboard shortcuts:
```
m -- take frequency measurement
n -- take counter measurement
w -- focus waveform
f -- focus frequency
d -- focus duty cycle
a -- focus amplitude
q -- exit
+/s -- increments selected digit
-/x -- decremenets selected digit
```
For `w/f/d/a` if the control is already focused, it focuses its counterpart in the other channel.