Buying 0~10MHz Spectrum analyzer, solutions and advice

[Frex]

Hello,

For all my audio measurements, i use my external ADC unit. Like a soundcard, it's an audio ADC chip, supporting sampling rate only up to 192kHz.
With a good software tool (like Spectraplus or others), make accurate measurements of many parameters is very easy.

But, unfortunately, as soon frequency is above some tens of kHz, the Nyquist limit is reached and sometime a part of the signal is not displayed...
(for example all the out of band noise of oversampling DAC).
Sometime, it can be very useful to know the spectrum shape above the 100kHz limit of soundcard.

Therefore, i look since many weeks what would be the better choice to satisfy my need.
First, i list below my preliminary need for this spectrum analyzer ;

0 to about 10MHz bandwidth (or more)
High sensitivity (µV range)
User friendly interface
Small from factor (i don't have much space !)


With just these parameters, i have selected few devices after many long time using our preferred web search engine,
and the result is listed below.

SignalHoud USB SA44 (750€)
RIGOL DSA1020 (3000€)
Picotech Picoscope 4224 (750€)
Handyscope HS3 (€)
Cleverscope CS320 (€ )
Bitscope BS325 (560€+shipping)
Agilent HP8568B 100Hz-1.5GHz Spectrum analyser USED (1500€+shipping)

Unless otherwise noted, all prices include VAT and shipping to my country (France).
(For more info about each device, you can click to go on it's main web page.)





SignalHoud USB SA44 (800€)
The SA44 is a new device, i'ts a small box connected to a PC, with a specific software to control it.
It can perform spectral analysis in the range of 1Hz to 4GHz.

It seem to be a very interesting device, above all with that price.
Unfortunately, we have no background for tis device and i find only official info about this unit.
Many real example of use of this unit is missing on the mfg web site, and it's hard to really know if the SA44 work well in the bandwidth of 0-10MHz.

pro:
wide bandwidth.
reasonable price.
small.

cons:
no background of how it work and it LF performance.
50 Ohms inputs not convenient for LF use.
computer needed.

RIGOL DSA1020 (3000€)
The Rigol DSA1020 is also a new product only available since some months.
Unlike the SA44, it's a real stand-alone tool, similar to an digital Oscilloscope.
The DSA1020 is a 9kHz to 2GHz spectrum analyzer, with many advanced functions. It's also the more costly solution...

pro:
performance
stand-alone , easy to use.
high dynamic range
very versatile
Large color screen,USB, Ethernet

cons:
Frequency start to 9kHz
Resolution bandwidth limited to 100Hz.
50 Ohms inputs not convenient for LF use.
Price


Picotech Picoscope 4224 (750€)

The picoscope is not mainly a spectrum analyzer, but the 4224 is a 12 bits 40Ms/s USB DSO. The software supplied with the 4224 is very powerful and allow to display spectrum (using FFT) between 0 to Fs/2. The 4224 offer all advanced 2 channels DSO functions. An averaging mode allow to push the ENOB from 12 to up to 16 bits, improving significantly the noise floor of the spectral analysis.
Demo software is downloadable on picotech web site.

pro:
Good performance
DSO channels functions 80Ms/s.
1Mpts FFT
versatile
reasonable price.
1M input impedance

cons:
Not a real spectrum analyzer
computer needed.


Handyscope HS3-25 (900€)

Like the Picoscope, the Handyscope HS3 is a USB DSO.It also allow spectrum analysis using FFT.
Price depend on the sampling rate you choose, but for 10MHz bandwidth, the HS3-25 (25Ms/s) is sufficient.
It's a 12bits ADC, but effective resolution depend on the sampling rate.
The biggest issue with this device, is the software...(only my opinion).
Demo software can be downloaded on the mfg web site.

pro:
Several auto measurement
Small
Reasonnable cost.

cons:
Very poor software interface (only my own opinion)
Resolution is dependent of sampling rate (8bits at 100Ms/s)
FFT only 32kpts


Cleverscope CS320 (1500€)
Another USB DSO, with FFT spectrum analysis.
High sampling rate, 12 bits.

pro:
Poor software

cons:
computer needed.


BitScope BS325 (€)

It seem to be a great product with good support and evolute software.
The demo software is convincing, easy to use.
It include a signal generator, 2 channels DSO, spectrum analyzer, logic analyzer
(8 digital inputs) and more.
It's a 40Ms/s ADC with
The interface can be USB or Ethernet.

pro:
very good software
generator and logic analyzer
signal generator, digital inputs
small

cons:
Not a real SA
low resolution (8 bits)
computer needed.

Agilent HP8568B 100Hz-1.5GHz Spectrum analyzer USED (1500€+shipping)

My first way to search a spectrum analyzer had to buy a HP8568, because it seems to be a logic choice.
Unfortunately, the selling price of this older unit is high (1500€ or more aften without any warranty!),
and it's very high weight (75kg i think) to make shipping extremely costly (often more than the price of the unit !).
The all these reason, i prefer to buy other thing.





It would be interesting if anybody have an experience with these units.
At this time, the DSA1020 have my favor, but i'm not yet decided i think that i'm probably not the only one which look for
this type of instrument.
Thank you.


Frex.

[jcx]

packaged products are nice but lag behind available monolithic ADC chips, 18 bit @ 2MHz, 16 bit @ >80 MHz are available with ~US$200-400 demo boards

may need fpga or dsp companion hardware to collect/buffer at full speed so system cost will be higher

[bocka]

Hi Frex,

sorry to say but it's better to save your money than buying anything of this crap. A spectrum analyzer ist still very costly. Although the Rigol looks still decent on paper (but this is a RF spectrum analyzer as well as the used HP item and the SignalHoud) you have to check out it on your lab. You'll see that any of them have some inacceptable weaknesses. A spec is still a $$$$$ part.

I wouldn't buy a used spec until it comes directly from Agilent, R&S, Tek or some other first class Mfr. If a used one fails you can throw it away in most cases.

[Pano]

I've used the picoscope (several years ago) and it's not bad. I know that a lot of folks don't find it "serious" enough. But it did what it was advertised to do and was easy to use. I found the spectrum analysis function very useful.

[Frex]

Hello,

Jcx,
do you know and had you try on of this EVM ?
I know some, but the provided software don't allow many option, and is it slower...
(i have try the evm software of TI and AD).


bocka,

I understand that 1000€~3000€ device can't be so good as a Tektronix or Agilent devices ten times more costly. Nevertheless, it can be also a very good compromise.
Like my DS1022CD Rigol DSO, 5x lower priced than a Tektronix DSO and fitting very well to my hobbyist need !

panomaniac,
Thank you for your opinion, but did you have yet a Picoscope ?



Frex

[wakibaki]

You have a Rigol DS1022CD? Does this not have FFT built in?

w

[Frex]

Yes wakibi.
It's not very usable as most DSO, vertical resolution is too low ( 8 bits).
It is why i look for high resolution DSO (12-16bits), like Pico and others.

Frex.

[bocka]

Originally Posted by Frex

Hello,
I understand that 1000€~3000€ device can't be so good as a Tektronix or

I ordered a Hameg HMS3000 some month ago as the price (about EUR 3,000) seems very promising for 3GHz spectrum analyzer. But when tested that part what a disappointment. I thought this was a bargin for the money but that part was that faulty, noisy, slow and so on that only after 2 days I sent the part back. Better to buy a used R&S (or similar) for about EUR 6,000 or just forget it. Not worth the money.

[ChrisA]

Originally Posted by Frex

...
But, unfortunately, as soon frequency is above some tens of kHz, the Nyquist limit is reached and sometime a part of the signal is not displayed...
(for example all the out of band noise of oversampling DAC).
Sometime, it can be very useful to know the spectrum shape above the 100kHz limit of soundcard.

You CAN see any frequency you want using only the typical 192K sample per second audio interface. The trick is to "heterodyne" the signal down to the audio range. Using this you can measure signals well up into the MHz range but you are limited to the same 100Khz bandwidth by Nyquist. But by tuning the frequency of a local oscillator you get to select which 100K bit of bandwidth you can see at one time. Basically you place a primitive kind of AM radio receiver in front of the audio interface.

Actually you can see up to 192Khz of bandwidth at a time by taking advantage of the fact that your audio interface has two channels and quadrature sampling but that is not so easy and requires different software

[ghg]

24bit/ 625ksps, $199 + shipping
http://focus.ti.com/lit/ug/sbau147/sbau147.pdf
Got one, works perfect.


24bit/ 4Msps, $400 + shipping
http://www.ti.com/litv/pdf/sbau162