AliExpress $30 35MHz-4.4GHz ADF4351 Touchscreen Signal Generator - Page 1
Forum section: electronics / testgear

author: bb1
author_rank: Regular Contributor
timestamp: September 11, 2020, 02:26:35 pm
content: Here is short report on the output signal waveforms and spectra of AliExpress touchscreen ADF4351 board.

author: bb1
author_rank: Regular Contributor
timestamp: September 11, 2020, 04:01:49 pm
content: The lowest ADF5451 frequency permitted by AliExpress touchscreen is 35 MHz.Steady state spectrum near it is shown on attached picture.Another attached figure shows how output frequency is changed in first 80 uS after the output is enabled.

author: bb1
author_rank: Regular Contributor
timestamp: September 11, 2020, 04:05:47 pm
content: The first picture attached here.

author: maximvs
author_rank: Newbie
timestamp: November 24, 2020, 11:18:12 pm
content: I wonder if it is possible to take out the 25Mhz crystal and always provide an external RF source.I have a 10Mhz. clock (GPS Sync), which has a very pure output, and I'd like to use that.My question is:I read the specs on the ADF4351 and it is not clear if the reference signalshould be square wave or could be a sine wave. Any thoughts ?I might buy another unit and do a test but I'd like to hear what you guys think.

author: radiolistener
author_rank: Super Contributor
timestamp: November 25, 2020, 03:53:29 pm
content: There is more interesting ADF4351 development board on aliexpress:https://www.aliexpress.com/item/33032121416.htmlTwoADF4351+IAM81008+AD8307+ STM32F103C8T6 on the board.First ADF4351 is used as LO and second ADF4351 is used as tracking generator. Two ADF4351 allows to avoid spurs for bode plot.Can be used as signal generator, spectrum analyzer and tracking generator.Price is 24 USD. I just ordered one, it looks very interesting as a signal source and bode plot for 35M-4400M.

author: BugKiller
author_rank: Newbie
timestamp: November 25, 2020, 05:20:42 pm
content: Entirely coincidentally, just before I saw this post I ordered the "MAX2870 23.5-6000MHz RF Signal Source Generator Module" for US$52 (I have background with Maxium based products). Should be interesting to compare.I am like a kid in a candy store on AliExpress, always running a multi-page Wish List.

author: maximvs
author_rank: Newbie
timestamp: November 28, 2020, 09:09:13 pm
content: Unbelievable! I just ordered one. I'll do some testing when it gets here and post my results.

author: mawyatt
author_rank: Super Contributor
timestamp: December 01, 2020, 04:10:33 am
content: Just received the ADF4351 Touchscreen board we ordered awhile back. A quick test and it seems to work, had a problem with Setting menu but its resolved.Here's some quick results at various frequencies. Not too bad, but the frequencies are low (~-9ppm @ 200MHz) so evidently the reference XO is low. Now that the "setting" menu is active you can change the Ref Clock but only 3 decimal places of precision, not enough resolution to correct the -9ppm frequency error accuratelyBest,

author: bob91343
author_rank: Super Contributor
timestamp: December 01, 2020, 06:26:39 am
content: What about amplitude calibration? Modulation?

author: bb1
author_rank: Regular Contributor
timestamp: December 01, 2020, 12:13:29 pm
content: Karl-Heinz Schweikert found commands to control the board via USB serial port.I copy his post here:Here the secret of USB serial control:Baud:115200, Data:8, Stop:1, Parity:none, Type:Hex, Send on Enter:nonePoint: send 11 bytes B0..B10with B0:ad; B1:01=ADF4350,02=ADF4351; B2:01=point; B3:01=0dB,02=-3dB,03=-6dB,04=-9dBB4-6:fRef (03 d0 90 = 25.0000 MHz); B7-9:fPoint (03 0d 40 = 200.000 MHz); B10:sum(B0..9) & 255Stop: send 3 bytes B0..B2with B0:ad; B1:ff; B2=acSweep: send 18 bytes B0..B17, with B2:02=sweep; (others same as Point)B7-9:Start; B10-12:Stop; B13-15:Step; B16:01=kHz,02=MHz; B17:sum(B0..16) & 255Return on success: ad 66 13Example:ad 02 01 01 03 d0 90 00 88 b8 54 = ADF4350,Point,0dB,fRef=25.0000,f=35.000ad ff ac = Stopad 02 02 01 03 d0 90 0a ae 60 0c 35 00 00 13 88 02 0b = ADF4351,Sweep,0dB,fRef=25.0000,f=700.000..800.000MHz, Step 5.000MHzNice to use a small Python script to set a defined frequency, and e.g. read a filter response with logarithmic RF detector+Arduino, before switching to next frequency. Mixed operation with remote und manual works fine.

author: mawyatt
author_rank: Super Contributor
timestamp: December 01, 2020, 02:52:08 pm
content: Quote from: bob91343 on December 01, 2020, 06:26:39 amAmplitude at 300MHz is -9.07, -6.15, -3.20 and -0.04dBm @ 4 amplitude settings which should be 3dB apart. A sweep to 3.2GHz produces reasonable flatness, can't go past 3.2GHz as I have no means to evaluate performance. There is no modulation capability, but has a SMA input for an external reference. The internal 25MHz XO reference signal is supplied to this SMA, and checking the PCB it seems you can reroute the external SMA by changing a couple SMD components.This is basically a PCB with a ADF4351 chip without any additional chips in the RF chain, so expect typical ADF4351 data sheet performance. Not a bad little device for ~$30 IMO.Best,

author: bob91343
author_rank: Super Contributor
timestamp: December 01, 2020, 07:13:57 pm
content: Without some means of modulation this thing has limited application. One could build an analog amplifier with AM capability but FM is another story.So what we have is pretty much just an oscillator that could be used as the starting point for a signal generator.

author: ledtester
author_rank: Super Contributor
timestamp: December 01, 2020, 08:40:30 pm
content: Quote from: maximvs on November 24, 2020, 11:18:12 pmhttps://youtu.be/UFp4GFxFYcoand the previous video:https://youtu.be/SNuPzkJFMwY

author: radiolistener
author_rank: Super Contributor
timestamp: December 19, 2020, 11:22:01 am
content: Quote from: radiolistener on November 25, 2020, 03:53:29 pmI got it. Here is my first impression and some measurements for this unit:https://www.eevblog.com/forum/rf-microwave/sdr-rtl-nwt4000-hackrf-what/msg3376978/#msg3376978At a glance 45-50 dB dynamic range up to 1.5 GHz and about 30-40 dB up to 4.4 GHz. But response is not flat above 1.5 GHz.I got it for 20.49 USD by using discount and coupons. I expected a little better performance, but still not so bad for the price.The output impedance according to my measurements is about 40 Ohm. It works from 33 MHz to 4400 MHz and has pretty flat amplitude level. tested it from 35 to 1.6 GHz with RTLSDR. At 1.6 GHz frequency it has some little drift for about 500 Hz/minute, but I'm not sure if the source of drift is LTDZ board or RTLSDRv3 itself.Input impedance is about 29 Ohm and SWR is about 1.5 - 1.7. but very flat from 40 to 1500 MHz. Don't have equipment to check higher frequency. It looks that there is needs to remove 50 Ohm resistor on the input before mixer. But it looks that output level will be too high for the input and it will require 10 dB attenuator for bode plot.

author: radiolistener
author_rank: Super Contributor
timestamp: December 19, 2020, 12:22:50 pm
content: Quote from: bb1 on September 11, 2020, 04:01:49 pmI tested LTDZ and it looks that the lowest frequency that ADF4351 can produce is 33 MHz.Here is 33, 34 and 35 MHz from ADF4351 on the oscilloscope:

author: maximvs
author_rank: Newbie
timestamp: December 20, 2020, 06:53:13 pm
content: I made a video on my mods to the ADF4351> This is my first video so I am sorry for the "not great" quality. I will make an update though. Here it is:

author: mawyatt
author_rank: Super Contributor
timestamp: December 21, 2020, 12:05:35 am
content: Nice work!!Do you have the ability to do some narrow band measurements like I've posted a few threads above, especially since you are using an external reference which I assume has excellent phase noise?I was impressed with what the ADF4351 can accomplish. Kind of a "poor persons RF signal source", doesn't have any modulation capability, nor large output range scaling, but not bad for ~$30 IMO.Best,

author: EV
author_rank: Frequent Contributor
timestamp: January 01, 2021, 11:21:29 am
content: I bought also this touch screen generator. I attached some picture of its square waves. They are taken from my Tektronix 7904 scope with 7T11 and 7S11 (with S-4) plugins installed.

author: EV
author_rank: Frequent Contributor
timestamp: January 03, 2021, 12:13:00 pm
content: I attached some more pictures of wave forms. Amplitude is 250 mV on 100 MHz square wave but it is 450 mV on 4 GHz sine wave. Amplitude setting is the same in the generator all the time.It looks that the peak to peak amplitude is nearly same on all different frequencies.

author: EV
author_rank: Frequent Contributor
timestamp: January 03, 2021, 12:42:34 pm
content: As the rise time of the generator is about 70 ps (look at attached picture) the BW of the generator is 350/ 0.070 = 5 000 MHz. It means that this generator can show square wave correctly to 5000/5 = 1000 MHz and more accurately only to 5000/10 = 500 MHz. You can notice this on the pictures of previous post.

author: ledtester
author_rank: Super Contributor
timestamp: January 04, 2021, 10:43:16 am
content: Tony Albus has just done a review and comparison of a MAX2870 touchscreen module:https://youtu.be/DFtC7icVr-EApparently uses exactly the same PCB as the ADF4351 offering.

author: EV
author_rank: Frequent Contributor
timestamp: January 04, 2021, 07:20:17 pm
content: The rise time of this generator is so fast (70 ps) that it can be used to measure scopes rise time.I attached a picture where can be seen that rise time of my Tektronix R7103 scope with 7A29 and 7B10 plug ins is about 290 ps.So the BW of this scope is about 350/290 = 1.2 GHz.

author: EV
author_rank: Frequent Contributor
timestamp: January 05, 2021, 09:28:30 am
content: I attached a picture where can be seen that the rise time of my Tektronix 2465B scope is about 0.84 ns.So the BW of this scope is about 350/0.84 = 417 MHz.

author: andymok
author_rank: Contributor
timestamp: November 03, 2021, 09:53:17 am
content: Quote from: EV on January 05, 2021, 09:28:30 amI am also looking one for calibrating my 2445BDoes anyone know whether ADF4351 or MAX2870 module has better Fq accuracy?

author: bob91343
author_rank: Super Contributor
timestamp: November 03, 2021, 11:37:15 pm
content: I see AliExpress no longer has this item avalable.

author: andymok
author_rank: Contributor
timestamp: November 04, 2021, 01:58:22 am
content: There are still quite a few supplying the modules on Taobao, our go-to place in Hong Kong.

author: markl17@gmail.com
author_rank: Newbie
timestamp: March 14, 2022, 12:16:35 pm
content: 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

author: bob91343
author_rank: Super Contributor
timestamp: March 14, 2022, 09:46:56 pm
content: 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

author: jundar
author_rank: Contributor
timestamp: August 16, 2024, 03:56:17 pm
content: 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

author: DaneLaw
author_rank: Frequent Contributor
timestamp: August 16, 2024, 05:57:46 pm
content: Quote from: jundar on August 16, 2024, 03:56:17 pmThere 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 fromhttps://www.aliexpress.com/item/1005005387939878.html(not an active listing, just info and what differs.)Here a sweep up to around 800Mhz.. seems pretty linearPicture 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.

author: coromonadalix
author_rank: Super Contributor
timestamp: August 16, 2024, 06:00:37 pm
content: what is the lowest output db value out of theses

author: shabaz
author_rank: Frequent Contributor
timestamp: August 16, 2024, 06:38:58 pm
content: Quote from: coromonadalix on August 16, 2024, 06:00:37 pmI 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.

author: jundar
author_rank: Contributor
timestamp: August 19, 2024, 02:34:51 am
content: Quote from: DaneLaw on August 16, 2024, 05:57:46 pmMay you chance and possibility to meter a rise time at as low as possible frequency? I need a rise time less than 0.8ns to check the bandwidth of my oscilloscope.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: August 19, 2024, 04:02:38 pm
content: Quote from: jundar on August 19, 2024, 02:34:51 amToo fast risetime for my habengut (gear)..