Like many of you, I lust after good test & measurement equipment, but sometimes one’s budget forces compromise. So, I splurged – but only a little – and picked up a couple of signal sources that cover a good chunk of spectrum – from 0 to 4.4 GHz. The good news is, they ain’t half bad.

After browsing the wares on AliExpress, I chose a 25 MHz DDS AWG (direct digital synthesis arbitrary waveform generator) for $45 (USD, shipping extra) and a 4.4 GHz PLL synthesizer for $55 (free shipping). As the synthesizer bottoms out at 35MHz, I am left with a coverage hole from 25-35 MHz, but I expect I must have something in the lab to cover that.

Leading on from my reverse engineering project to re-create the firmware for the FG-100 unit, this is a project to build a function generator from scratch. Fixing many of the shortcomings of the FG-100 unit.

I found a cheap kit XR2206 Function Signal Generator DIY Kit Sine Triangle Square Output 1HZ-1MHZ that seems to suit for me well.

A look inside Rigol’s new function/arb generator reveals unexpectedly high build quality for a Chinese product..

The Owon AG051 and AG051F single-channel multifunction generators from Saelig produce standard and arbitrary signals at up to 5 MHz for under $200. Housed in 9.25×4.3×11.6-in. benchtop enclosures, these DDS-based instruments deliver 125 Msamples/s with 14-bit vertical resolution.

The AG051 and AG051F cost $185 and $199, respectively.

http://www.saelig.com/product/ag051.htm

Siglent’s new arbitrary waveform generator is a pro-level instrument for a (well-off) hobbyist price.

Siglent sent me their very new SDG2042X arbitrary waveform generator (AWG), which is made in China, and, well, American competitors may find themselves squeezed by the product. It’s in a hefty metal box with a plastic handle and shock protectors and feels as solid as anything from the big guys. If “Siglent” were erased from the label I’d assume it was from Keysight or Tektronix.

Siglent costs $500 and the others are (at least) ten times the price.

The unit has two independent and duplicate channels. So you’re getting two AWGs in one.

For the basic built-in waveforms memory is sampled at 300 MS/s. However, and possibly uniquely to this unit, another clock interpolates the data four times for each sample period. The result is an effective rate of 1.2 GS/s. Now, that’s on the built-in signals like sine, square, etc. For arbitrary waveforms the unit samples at 75 MS/s.

Siglent’s new arbitrary waveform generator
http://www.embedded.com/electronics-blogs/break-points/4440636/Siglent-s-new-arbitrary-waveform-generator

Reverse engineer the FG-100 pinout and develop alternate firmware that improves some of the shortcomings of the default firmware.

The FG-100 is a cheap function generator available off Ebay.

Unit is powered by an ATMega48 (socketed 28pin DIP), waveforms are generated using an 8Bit R2R ladder off of PORTD. As the micro is socketed I will be developing the alternate firmware using a pin compatible ATMega328P.

After a couple more hiccups with gcc-avr and optimisations I have a waveform being generated on a breadboard emulation of the FG-100 R2R DAC.

Tim Savage wrote 5 days ago

Just dropped the micro into the FG-100 and everything worked as expected. I’ve got a lot of work to do on the firmware now.

EEVblog #806 – Siglent SDG2000X Arb Function Generator First Look
https://www.youtube.com/watch?v=_Mup2VnXH_k

Dave takes a look at the new Siglent SDG2122X / SDG2042X Arb Generator and compares it to the Rigol DG4162 and the older Siglent SDG5082.
1.2GS/s arb gen for US$499!