Choosing between entry-level 12-bit DSOs

[Mechatrommer]

this is +1 imho in rigol, lets not forget, the 2 scopes discussed here got pros and cons.

Since the Siglent can into 2 Gsa/s, it could potentially be modded to support at least 800 MHz single-channel bandwidth, if there are no further limitations in digital signal processing and/or software. I don't recall anyone mentioning or trying this though.

i posted this earlier in this thread, some people said its very rare case. now we have 2 person asking for it so i'm not so rare, lets wait HAM fellows (names with numbers and who build their own radio) to chime in what they have to say, cheers.

[gf]

The Rigol is applying the theory correctly and the Siglent can't possibly be doing an infinitely wide reconstruction, so... 

But you have the choice to implement either

• a truncated/windowed sinc filter with a n*sampe_rate...(1-n)*sample_rate transition band (symmetrical around 0.5*sample_rate),
• or an ordinary steep lowpass filter with a n*sampe_rate...0.5*sample_rate transition band,

where 0<n<0.5 (for example n=0.4).

Contrary to what you might intuitively believe, it's the latter which does what people here seem to expect when it comes to frequencies beyond the filter's reconstructability limit of n*sample_rate. But it requires more DSP resources.

[pdenisowski]

lets wait HAM fellows (names with numbers and who build their own radio) to chime in what they have to say

Depends on the kind of radio you're building (or operating)   In the United States, there are amateur allocations at 902 MHz and 1240 MHz, and some experimenters go even higher.

https://www.arrl.org/files/file/Regulatory/Band%20Chart/Band%20Chart%20-%2011X17%20Color.pdf

One of my commercially-produced radios (the Icom 9700) has 144, 440, and 1200 MHz,  Icom is also investigating making amateur transceivers for the 2.4 and 5.6 GHz ISM bands

https://www.icomjapan.com/api/download.php?page_id=66&fl=JTJGdXBsb2FkcyUyRmxwJTJGc2hmJTJGU0hGX3Byb2plY3Rfdm9sMV9lbmcucGRm

73, Paul, KO4LZ

[Mechatrommer]

nice story but anything 1GHz and above is not relating to this thread... 140,144,902MHz maybe related. if you have one of this https://www.ebay.com.my/itm/114448357711 it would be nice to see the signal in time domain... ymmv.

[Fungus]

iircsomeone stated dho800 only works on specific brand. i have few wifi adapter here, maybe later i will try. but still, its a few more steps to do... rather than plugin usb stick and hit capture button. ymmv.

It's literally the most common chipset/brand.

I never take the WiFi dongle out. Apart from the web interface you can save all screen captures, data dumps, etc., to the internal memory and accessed via ftp as if they were local files on my PC.

You also get correct date/time stamps on the files if it's connected to WiFi.

[KungFuJosh]

@KungFuJosh can you please set the scope to 500 Msa/s, low waveform acquisition rate (to make the TinySA's glitches less visible), low persistence, and record a video of a 30 seconds long frequency sweep from, say, 110 MHz to 270 MHz?

Coax connection with a 50 Ohm feed-through terminator, if possible, to make the test conditions the same as in my test.

It will be interesting to see at what frequencies (and at what ratio relative to the sampling rate) it will become first wobbly and then AM-like (if it will), to compare that to Rigol.

I'd love to play, but I don't have one of these scopes. I have an SDS2504X+ 500MHz scope. I can sweep up to 841MHz on my scope with the TinySA Ultra.

[shapirus]

I'd love to play, but I don't have one of these scopes. I have an SDS2504X+ 500MHz scope.

Well, it would still be an interesting data point. What's the lowest samples/sec rate it can do? The idea is to set it to the lowest sampling rate and connect it to a source that outputs a frequency sweep in the range from ~20% to ~60% of the sampling rate.

We can then speculate if the Siglent's 800 HD series have the same wave reconstruction implementation as yours, or not :).

I can sweep up to 841MHz on my scope with the TinySA Ultra.

It can actually output up to 5.4 GHz (or at least so the specs say), but it switches from sine to square wave above 800 MHz.

[Fungus]

I'd like to know what the Siglent does on a real AM waveform, too.

Feed in the 220MHz signal at 500MSamples/sec. but add some AM modulation and see if it reproduces it (eg. 16MHz modulator).