AliExpress $30 35MHz-4.4GHz ADF4351 Touchscreen Signal Generator

[andymok]

There are still quite a few supplying the modules on Taobao, our go-to place in Hong Kong.

[markl17@gmail.com]

Hi the max2870 device from AliExpress has resolution of 1khz is that hardware or it can be modified and if so did one tried something like that

[bob91343]

https://www.aliexpress.com/item/1005003510090960.html?spm=a2g0o.productlist.0.0.44ad33a1kjphp3&algo_pvid=9bacbec1-bf5a-47f5-bb40-7023315fb704&algo_exp_id=9bacbec1-bf5a-47f5-bb40-7023315fb704-1&pdp_ext_f=%7B%22sku_id%22%3A%2212000026110079845%22%7D&pdp_pi=-1%3B15.52%3B-1%3B-1%40salePrice%3BUSD%3Bsearch-mainSearch

[jundar]

Is any chance the MAX7280 based generator has similar signal rise time and it is possible to use it to check bandwidth of oscilloscope as well? I have some doubs regarding my Siglent SDS2104X Plus ("upgraded' to 500MHz) and going to order MAX7280 based board and use the rise time to check the oscilloscope bandwidth. Thank you for any information!

link: https://www.aliexpress.us/item/3256806244969667.html

[DaneLaw]

Is any chance the MAX7280 based generator has similar signal rise time and it is possible to use it to check bandwidth of oscilloscope as well? I have some doubs regarding my Siglent SDS2104X Plus ("upgraded' to 500MHz) and going to order MAX7280 based board and use the rise time to check the oscilloscope bandwidth. Thank you for any information!

link: https://www.aliexpress.us/item/3256806244969667.html

There are two variants of these small touchscreen optimised MAX2870 based signal gens.
Beside the one you link to, there is also this model.. it got a red ribbon around the PLL MAX2870 info.. the UI & features seem to differ between them.
// Got my unit from https://www.aliexpress.com/item/1005005387939878.html (not an active listing, just info and what differs.)

Here a sweep up to around 800Mhz.. seems pretty linear

Picture lower span to 790Mhz (TinySA4 Ultr.)


Sweep 6150 to 6510Mhz dropping, as MAX2870 is far from linear up there, but then again, neither is TinySA4..


Its a halfbacked chinese mashup product, at least the variant above.. haven't tried the other.

[coromonadalix]

what is the lowest output  db value out of theses

[shabaz]

what is the lowest output  db value out of theses

I tried the one in the photo, and the few discrete values that can be set in the touch-screen interface do not actually match what is output. The screenshot shows the actual result at the four configurable output levels, at a spot frequency (the chosen spot frequencies are slightly different each time just to display it like that, no other reason).

When set to the max level, the output is reasonably flat (to within about 1 dB) from LF to approx 4 GHz, and then tails off a bit (maybe a couple of dB). I didn't test the other output levels across the spectrum, because I figured I'd just use it at the max output and attach an external attenuator if required.

I think the device is OK for the price (by OK I mean kind of average : ), but could be better. They are not getting the best output from the chip. Also, there are some bugs (e.g. sweep is temperamental). But not bad if you need a single frequency generated for a purpose. Harmonics are as expected, they will need to be dealt with if it matters to whatever use-case the device is needed for, and spurs are quite low, especially up to VHF or so, then a bit higher.