Spectrum Analyzer - Rigol DSA815

[hpux735]

That seems pretty reasonable to me.  I'm amazed about WWV, so much for using that to calibrate machines!

[ted572]

Introduction to using 'TG Power Sweep'.  See the attached PDF titled 'DSA815-TG, TG Power Sweep Mode'.

Edited Feb. 7, 2015: Revised the PFD document.  See it here -> https://www.eevblog.com/forum/testgear/spectrum-analyzer-rigol-dsa815/msg603946/#msg603946[/url]

[N8AUM]

Introduction to using 'TG Power Sweep'.  See the attached PDF titled 'DSA815-TG, TG Power Sweep Mode'.

Yes, a very handy feature, too bad it doesnt work with my 815 

[Howardlong]

Introduction to using 'TG Power Sweep'.  See the attached PDF titled 'DSA815-TG, TG Power Sweep Mode'.

Yes, a very handy feature, too bad it doesnt work with my 815 

Same here, and that document was the basis of my tests.

[N8AUM]

Introduction to using 'TG Power Sweep'.  See the attached PDF titled 'DSA815-TG, TG Power Sweep Mode'.

Yes, a very handy feature, too bad it doesnt work with my 815 

Same here, and that document was the basis of my tests.

Rigol told me to send it back for an exchange.
Wish I could try with older firmware but I have the rev 04 bootloader so can only try it with 09 or 12 firmware.
 

[orbiter]

Doesn't work on mine either using the exact settings shown in the .pdf

[ted572]

TG Power Sweep works for me with firmware .12.  Did you connect a coax cable between TG Output and SA Input before selecting the 'Power Sweep' settings?.  You should see a ramp up to 10/11dB in 10 or 11 steps (I don't recall if it was 10 or 11).

[orbiter]

TG Power Sweep works for me with firmware .12.  Did you connect a coax cable between TG Output and SA Input before selecting the 'Power Sweep' settings?.  You should see a ramp up to 10/11dB in 10 or 11 steps (I don't recall if it was 10 or 11).

Yes coax connected.. With settings all exactly the same as shown in the Rigol .pdf, I just get a flat-line at -20dB with both FW 01.12 & FW 01.09. Does your SA have the U1105 pins 7/8 jumper mod that keeps the trials alive?

[ted572]

TG Power Sweep works for me with firmware .12.  Did you connect a coax cable between TG Output and SA Input before selecting the 'Power Sweep' settings?.  You should see a ramp up to 10/11dB in 10 or 11 steps (I don't recall if it was 10 or 11).

Yes coax connected.. With settings all exactly the same as shown in the Rigol .pdf, I just get a flat-line at -20dB with both FW 01.012 & FW 01.09. Does your SA have the pin 7/8 jumper mod that keeps the trials alive?

Re. TG Power Sweep: No, I do not have U1105 Pins 7 and 8 connected together, as I have an older DSA818-TG (w/FW .12 now).  Maybe that is doing something to your unit.  I noticed that Howard's SA, and at least one other with his fix doesn't work either.  It will be interesting to see if this is the cause, although I hope not, and it kind of seems unlikely.

[N8AUM]

TG Power Sweep works for me with firmware .12.  Did you connect a coax cable between TG Output and SA Input before selecting the 'Power Sweep' settings?.  You should see a ramp up to 10/11dB in 10 or 11 steps (I don't recall if it was 10 or 11).

Yes coax connected.. With settings all exactly the same as shown in the Rigol .pdf, I just get a flat-line at -20dB with both FW 01.012 & FW 01.09. Does your SA have the pin 7/8 jumper mod that keeps the trials alive?

Re. TG Power Sweep: No, I do not have U1105 Pins 7 and 8 connected together, as I have an older DSA818-TG (w/FW .12 now).  Maybe that is doing something to your unit.  I noticed that Howard's SA, and at least one other with his fix doesn't work either.  It will be interesting to see if this is the cause, although I hope not, and it kind of seems unlikely.

Pretty sure that should be a standard feature regardless if the trail period has expired or not ? Correct me if I am wrong.

[Howardlong]

TG Power Sweep works for me with firmware .12.  Did you connect a coax cable between TG Output and SA Input before selecting the 'Power Sweep' settings?.  You should see a ramp up to 10/11dB in 10 or 11 steps (I don't recall if it was 10 or 11).

Yes coax connected.. With settings all exactly the same as shown in the Rigol .pdf, I just get a flat-line at -20dB with both FW 01.012 & FW 01.09. Does your SA have the pin 7/8 jumper mod that keeps the trials alive?

Re. TG Power Sweep: No, I do not have U1105 Pins 7 and 8 connected together, as I have an older DSA818-TG (w/FW .12 now).  Maybe that is doing something to your unit.  I noticed that Howard's SA, and at least one other with his fix doesn't work either.  It will be interesting to see if this is the cause, although I hope not, and it kind of seems unlikely.

FWIWI have the fix which doesn't stop writes to the FRAM, it just resets the time on boot up.

[ted572]

Introduction to using 'TG Power Sweep'.  See the attached PDF titled 'DSA815-TG, TG Power Sweep Mode'.

I revised my interpretation of the DSA815-TG 'Power Sweep' mode by adding more information on what I understand it does.  See the attached PDF file.  Any comments will be appreciated, so that we may understand what Rigol had in mind for this mode that was not fully documented in their DSA800 User Guide.

Edited  2/7/2015:  See latest version is at -> https://www.eevblog.com/forum/testgear/spectrum-analyzer-rigol-dsa815/msg603946/#msg603946

[hpux735]

The new DSA815 firmware 00.01.12.00.02 works well, retains all installed options, adds features, and fixes.

Wall-E..can you share the features/fixes list?

Here you go (one comment: I already had -30dBm on my TG before, not -20):

Change log : DSA800(DSP)Version Notes.doc
Version 00.01.12.00.02
Date 2014-11-10

• Increase the frequency offset function.
• Increase the switch between local and remote command.
• Increase the frequency of logarithmic function
• Increase the key lock function.
• Increase the traditional Chinese features.
• Increased access to frequency reference the status of a remote command.
• Increase sanitation function.
• Increase in Peak List can turn off the display line.
• Modify the option name information directly display option.
• Modify the Trace preservation order in CSV format, from a list of changes to the three column.
• To improve the quality of AM demodulation.
• Modify the “Clear All” for “Blank All”, and redefine the “Clear Write”.
• To solve the problem of inaccurate measurement of N dB.
• To solve the problem of freq Count is not accurate.
• To solve the problem of error loading an State file
• To solve the problem TX1000 instrument connection after the crash.
• The lower limit of TG range from -30dBm to -20dBm.

So, I finally upgraded from 1.09 to 1.12.  A few strange things:

The log frequency mode seems like it just takes a snapshot of the trace and re-scales it to be a log display.  The resolution on the low-frequency end of the trace is terrible, and the trace doesn't update.  Am I missing something?

Also, I looked at my licenses and it seems like some are missing, like the 10hz RBW.  But(!), I still have the ability to go down to 10hz RBW.  Is this standard now?

[ted572]

Also, I looked at my licenses and it seems like some are missing, like the 10hz RBW.  But(!), I still have the ability to go down to 10hz RBW.  Is this standard now?

hpux735:

The 10Hz RBW is still an Option in there, although it is not provided as a Trial because they don't sell it for the DSA815.  When it is activated it will NOT show up in the Official list like the Trials do.   Although once it is activated you will be able to find it listed as Option 0003 with the key code used to activate it in the Sys Info screens.

[hpux735]

Also, I looked at my licenses and it seems like some are missing, like the 10hz RBW.  But(!), I still have the ability to go down to 10hz RBW.  Is this standard now?

hpux735:

The 10Hz RBW is still an Option in there, although it is not provided as a Trial because they don't sell it for the DSA815.  When it is activated it will NOT show up in the Official list like the Trials do.   Although once it is activated you will be able to find it listed as Option 0003 with the key code used to activate it in the Sys Info screens.

Very interesting.  Thanks for clearing that up!

[ted572]

I purchased the following Return Loss Bridge (RLB) from eBay that is made in China.  -> http://www.ebay.com/itm/121495681786?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT    My interest was not because I needed one, I don't, but that I wanted to see how good it could be for $39.  This looks like a good option for people that do not want to build one, or don't have a lot of money to buy a good one.  From the data (see attachment) you can see that its Return Loss is essentially 40dB or better up to 450MHz, and much better than the Rigol VB1020, or the Mini-Circuits directional Coupler.  You can find data on the Rigol and Mini-Circuit units in my post at -> https://www.eevblog.com/forum/testgear/spectrum-analyzer-rigol-dsa815/msg583550/#msg583550   Remember that you need a very good 50 Ohm Termination to check the Capability/Calibration of your RLB.  You even need one for the $600 Rigol VB1020, because its not supplied with one.  If you don't have a good Termination one you will NOT know what its capability is.  I recommend the Mini-Circuits model KARN-50-18+, N male connector, 2 Watts, DC to 18GHz, $14 each Brand New (plus Tax and Shipping).  http://www.minicircuits.com/pdfs/KARN-50-18+.pdf   This is not a place to try to save money, as it is very important to know how well your RLB works, or even that it does.  If you buy one of these eBay RLBs your results may be a little better, or worse, but in any case this looks like a good option for a basic RLB.

Edit:  I just received a PM and was asked if I would sell it for $50.  It has just been sold for $45 with shipping.  I'm taking it to UPS now.

[ted572]

I haven't received any comments on the DS815 Power Sweep mode.  So I summed up my thoughts on what it does and how to use in the the provided attachment.  I changed my original PDF document to a JPG to make it easier and quicker to edit the original Rigol picture that was in error.  It was showing a 1.5dB Compression Point, rather than the correct 1dB Compression Point.

Edited 2/7/2015 to add some additional clarification to the picture and to provide a PDF document.
           Revised again:  Maybe this will help more for people not familiar with 1dB Compression measurement techniques.
   

[hpux735]

So, I made an LNA breakout board (based on the Skyworks 67015).  I used my DSA815 to measure as much as I could.  I know my methodology isn't perfect.  I'm interested in opinions for how I could improve my methods.  I couldn't get power sweep to work (I was using a zero span).  I just saw in ted572's post that he's using 100hz span.  I'll try that next time.  I don't understand doing power sweep and frequency sweep at the same time...  Anyway, here's the video if you're interested:

http://youtu.be/hA-5vE_2gG8

[ted572]

So, I made an LNA breakout board (based on the Skyworks 67015).  I used my DSA815 to measure as much as I could.  I know my methodology isn't perfect.  I'm interested in opinions for how I could improve my methods.  I couldn't get power sweep to work (I was using a zero span).  I just saw in ted572's post that he's using 100hz span.  I'll try that next time.  I don't understand doing power sweep and frequency sweep at the same time...  Anyway, here's the video if you're interested:

http://youtu.be/hA-5vE_2gG8

'Power Sweep' does NOT work with Zero Span.  The 'Power Sweep' occurs during the 100Hz Span (the Power Sweep).  The 100Hz Span in the example I provided.  If you used a wide Span then you would also be seeing the effects of the Bandwidth in the circuit under test.  So therefore you should always be using  a very small Span for the Frequency your making your measurements at.  Power Sweep is for checking  a circuit (Amplifier, Limiter, etc.) for Linearity by finding the 1dB Compression Point.

I would like to think that Rigol would have told us all this; rather than leave it to us to figure out what it does, is for, and how to use it.

Edit:  Changed (Sweep) in the second sentence to (the Power Sweep) to be sure that this is appreciated.

[hpux735]

Exactly. That's why I tried to do it with zero span. Dumb, dumb dumb. I'll have to try it with 100hz

[Teneyes]

Yes 'Sweep' is mostly referring to a variation in the Frequency. Maybe a term like , " Power dynamic range" or "Power Linearity range" of DUT is better?

Why are there steps in the plot?  are there Changes of internal attenuations ?

[ted572]

Yes 'Sweep' is mostly referring to a variation in the Frequency. Maybe a term like , " Power dynamic range" or "Power Linearity range" of DUT is better?

Why are there steps in the plot?  are there Changes of internal attenuations ?

Edit: Content revised 2/10/015

The D815-TG 'Power Sweep' mode is for testing an Amplifier, etc. for its Output Linearity.  Such as the 1dB Compression Point, etc.

Pages 2-42, 43 of the Rigol DSA800 User Guide shows that Power Sweep steps up 1dB in amplitude as frequency span increments up.  Rigol may not have explained the Power Sweep mode sufficiently, leaving some users not appreciating it fully, or understanding what its purpose is.

Power Sweep provides an increase in TG output amplitude as frequency Span progresses.  The frequency Span is kept to a absolute minimum (100Hz) so that the test results aren't effected by the Bandwidth of the device being tested for amplitude input/output linearity.

You can determine if Power Sweep works in your DSA815-TG by connecting a coax cable between the DSA815-TG's 'TG Output' and 'SA Input', and then selecting the following settings:

Preset (Green key), FREQ: 750MHz (the Test Frequency), SPAN: 100Hz, RBW: 100Hz (Required if 10Hz RBW Option is installed),  TG: On, TG Level: -20dB, Power Range: 20dB, Power Sweep: On, AMP: Auto Scale, Scale/Div: 2dB, Ref Level: -1dB (or A/R).

You should see the results of Power Sweep with its 1db amplitude steps over a 20dB range.  Although 1 or more of the steps may have 2 steps lumped together as a 2dB ramp up (probably a Bug).

[orbiter]

As you, this mode seems to have confused many users, and consequently they may feel that Power Sweep is not working in their DSA815-TGs.  I believe they are probably all working fine, but due to Rigol not explaining the Power Sweep mode sufficiently (if hardly at all) has left many not understanding it in the least, and as a result seeing it as not functioning.

Edit:  If you connect a coax cable between the TG Output and SA Input and set the DSA with the Example Measurement Settings shown here -> https://www.eevblog.com/forum/testgear/spectrum-analyzer-rigol-dsa815/?action=dlattach;attach=134859  you will see the results of Power Sweep without going thru an Amplifier.  The results will show the amplitude steps, and be linear.

Just as a matter of interest.. I carried out the Power Sweep to the exact word again today with & without the trial mod. And on my unit the Power Sweep function does nothing at all..  As seen here..

[georges80]

Attached shows the power sweep on my 815. Coax cable from TG output to RF input.

cheers,
george.

[Tom D]

Here's the power sweep on my unit, same connection as George; coax cable from TG output to RF input.



Tom