Re: Measuring Phase with an analogue spectrum analyzer?
Time domain is better for this case. If you have an spectrum analyzer with full ?FFT ?support, for example N9020A. If you choose FFT the pase information are not available easily on display, you must to download the vector to a computer and analyze it. You must to check the pase difference between components, at this point analog demodulation are available form the most signal analysis packages. On my view is simpler an cheaper to perform a test with zero span if the only purpose ?is to check (AM OR FM ). ?
Ing. Patricio A. Greco
Taller Aeronáutico de Reparación 1B-349
Organización de Mantenimiento?Aeronáutico de la Defensa OMAD-001
Laboratorio de Calibración ISO 17025?AREA: RF/MW?
Gral. Martín Rodríguez 2159
San Miguel (1663)
Buenos Aires
T: +5411-4455-2557
F: +5411-4032-0072
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On 29 Mar 2023, at 12:24, Dave McGuire < mcguire@...> wrote:
?And this is even if the analyzer retains the phase information. Phase information comes along "for free" by the FFT, but is discarded in most FFT analyzers and the FFT functions in digital oscilloscopes.???????????-DaveOn 3/29/23 11:18, Blue Smoke Lee wrote:In order for displayed FFT phase information to be both meaningful and relevant, all the analyzer clocks/oscillators used in the down converters, ADC and FFT process must be coherent (in phase sync and related to) the ones used to generate the source signal. ?Otherwise the phase information, while displayed, has no reference and is meaningless. ??This is why a VNA, which are spectrum analyzers that also show phase relationships, has a built-in signal source or a reference connection to the signal source.
It doesn’t matter if the VNA uses swept signal or FFT processes to make the spectrum and phase measurement, the signal source side remains coherent with the analyzer side and with the shared phase reference, phase information is preserved and the display phase information is accurate and meaningful.
*Lee Pedlow*
/Solving business challenges through technical innovation./
On Mar 29, 2023, at 1:01 AM, Martin via <musaeum@...> wrote:
?I guess any FFT analyzer can show amplitude and phase. Are the ones you mention actually FFT analyzers, or how do they accomplish it?
Would it work on a scalar network analyzer if I can make the tracking generator phase locked to the carrier? In that case the internal electronics have the right reference to compare phase.
cheers
Martin?
--?Dave McGuire, AK4HZNew Kensington, PA
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Anyone have info on error 72, I can't find it in the manual.?
Thanks
Hank
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Re: Measuring Phase with an analogue spectrum analyzer?
And this is even if the analyzer retains the phase information. Phase information comes along "for free" by the FFT, but is discarded in most FFT analyzers and the FFT functions in digital oscilloscopes.
-Dave
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On 3/29/23 11:18, Blue Smoke Lee wrote: In order for displayed FFT phase information to be both meaningful and relevant, all the analyzer clocks/oscillators used in the down converters, ADC and FFT process must be coherent (in phase sync and related to) the ones used to generate the source signal. ?Otherwise the phase information, while displayed, has no reference and is meaningless. ?This is why a VNA, which are spectrum analyzers that also show phase relationships, has a built-in signal source or a reference connection to the signal source.
It doesn’t matter if the VNA uses swept signal or FFT processes to make the spectrum and phase measurement, the signal source side remains coherent with the analyzer side and with the shared phase reference, phase information is preserved and the display phase information is accurate and meaningful.
*Lee Pedlow*
/Solving business challenges through technical innovation./
On Mar 29, 2023, at 1:01 AM, Martin via groups.io <musaeum@...> wrote:
?I guess any FFT analyzer can show amplitude and phase. Are the ones you mention actually FFT analyzers, or how do they accomplish it?
Would it work on a scalar network analyzer if I can make the tracking generator phase locked to the carrier? In that case the internal electronics have the right reference to compare phase.
cheers
Martin
--
Dave McGuire, AK4HZ
New Kensington, PA
|
Re: Measuring Phase with an analogue spectrum analyzer?
In order for displayed FFT phase information to be both meaningful and relevant, all the analyzer clocks/oscillators used in the down converters, ADC and FFT process must be coherent (in phase sync and related to) the ones used to generate the source signal. ?Otherwise the phase information, while displayed, has no reference and is meaningless. ?This is why a VNA, which are spectrum analyzers that also show phase relationships, has a built-in signal source or a reference connection to the signal source.
It doesn’t matter if the VNA uses swept signal or FFT processes to make the spectrum and phase measurement, the signal source side remains coherent with the analyzer side and with the shared phase reference, phase information is preserved and the display phase information is accurate and meaningful.? Lee Pedlow Solving business challenges through technical innovation.
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On Mar 29, 2023, at 1:01 AM, Martin via groups.io <musaeum@...> wrote:
?I guess any FFT analyzer can show amplitude and phase. Are the ones you mention actually FFT analyzers, or how do they accomplish it?
Would it work on a scalar network analyzer if I can make the tracking generator phase locked to the carrier? In that case the internal electronics have the right reference to compare phase.
cheers
Martin
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Re: 8594E need documents for processor board and battery question
In both cases I removed the boards.? By the way, the analyzer with this battery was made in the USA and the one with a button cell was made in the UK.? I don't know if this is the case in all cases...
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Which spec an? 8563E or E4407B
I need a spec an for home lab use that covers 24 GHz. I am looking at a refurbed 8563E versus an E4407B at nearly twice the price, but a probably lot younger.
Can those who know both of these instruments well tell me which one they would choose for home lab use please? I need long term reliability more than anything else; moderate accuracy next.
Thanks!
Colin G4CWH
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Re: Measuring Phase with an analogue spectrum analyzer?
I guess any FFT analyzer can show amplitude and phase. Are the ones you mention actually FFT analyzers, or how do they accomplish it?
Would it work on a scalar network analyzer if I can make the tracking generator phase locked to the carrier? In that case the internal electronics have the right reference to compare phase.
cheers
Martin
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Nice work. Where did you get the nice mat with the sectioned parts bins?
Sam
W3OHM
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Re: Measuring Phase with an analogue spectrum analyzer?
A network analyzer can only track the phase difference between its reference and measurement channels, not the phase spectrum.
If you want to separate AM or FM components, you can use the AM/FM DEMOD function on the spectrum analyzer, and then connect to the low frequency spectrum analyzer for measurement.
Or a more modern way is to use a "vector signal analyzer", like the HP 89441A, AGILENT E4406A, N9020A, or even the cheaper RTL-SDRs, whose digital IF's I/Q components tell you the magnitude and phase changes.
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Re: E4407B Step Attenuator
Thanks Ken.
I have rebuilt these type of attenuators before but I chickened out on this one and sent it to Test Equipment Plus for a full rebuild since I had no way to do the test and certification that they do.
Maybe next time I'll tackle it. I do have a bunch of HP gear that has these attenuators in them so I plan to go through them one by one and do a wholesale O ring job on each one to fend off
the problems I had with this one.
Sam
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N9340B, N9342CN, and N9344C Options
Hello! I have a few handheld SAs that I'd like to add a few options to, but it seems I can't do trials anymore, at least through the Keysight website. Before I reach to a 3rd party reseller, etc, I'd figure I'd ask if someone here knows of a way.
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Re: Measuring Phase with an analogue spectrum analyzer?
Spectrum analyzers by their nature don't measure phase, only frequency. Vector Network Analyzers measure phase and frequency, but not really in the way you're thinking for differentiating AM from FM. Like the previous commenter pointed out, zero span will give you an "oscilloscope-like" amplitude vs time display on the spectrum analyzer.
A spectrum analyzer with a tracking generator is only a scalar network analyzer (aka doesn't measure phase, only amplitude and frequency).
Hi all,
do you know an analogue spectrum analyser able to measure phase?
The question came to my mind when playing with my freshly repaired W&G SNA1. I was looking at a 1MHz signal at various configurations of my signal generator in AM and FM. I started wondering how an AM spectrum is nearly identical to an FM spectrum although the signals are totally different on a scope (see the pics with a 1kHz modulation... which one is AM, which one FM?). I found out this is due to phase differences the analyzer cannot display.
The SNA1 being a network analyzer (i.e. having a tracking generator) and a phase display I tried that, but it didn't work either, the generator not being locked to the carrier. It might work if I could tell the generator to remain at exactly the carrier frequency...
So thats what prompted my initial question. Is there a variant of an SA capable of doing that, or a more or less sophisticated measurement setup?
cheers
Martin
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Re: Measuring Phase with an analogue spectrum analyzer?
… you will se the double frequency on FM case … is very simple to figure. I used to listen FM radios with an AM receiver tuning off the frequency carrier…? Iy you have residual AM or FM the sideband components appears asymmetrical … this is all the same thing…?
Ing. Patricio A. Greco
Taller Aeronáutico de Reparación 1B-349
Organización de Mantenimiento?Aeronáutico de la Defensa OMAD-001
Laboratorio de Calibración ISO 17025?AREA: RF/MW?
Gral. Martín Rodríguez 2159
San Miguel (1663)
Buenos Aires
T: +5411-4455-2557
F: +5411-4032-0072
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This is a great question. The only difference between narrow band FM and AM spectrum (sine wave modulant) is the phase of the components.. There are a way to know if you have an AM or FM signal… .you must to use zero span and see the trace. Its little complex to explain in english for me but if you made the right settings the modulation sine wave will double the frequency when you are tuned at the carrier frequency …?
Regards, Patricio
Ing. Patricio A. Greco
Taller Aeronáutico de Reparación 1B-349
Organización de Mantenimiento?Aeronáutico de la Defensa OMAD-001
Laboratorio de Calibración ISO 17025?AREA: RF/MW?
Gral. Martín Rodríguez 2159
San Miguel (1663)
Buenos Aires
T: +5411-4455-2557
F: +5411-4032-0072
On 28 Mar 2023, at 17:47, Martin via ??< musaeum@...> wrote:
Hi all,
do you know an analogue spectrum analyser able to measure phase?
The question came to my mind when playing with my freshly repaired W&G SNA1. I was looking at a 1MHz signal at various configurations of my signal generator in AM and FM. I started wondering how an AM spectrum is nearly identical to an FM spectrum although the signals are totally different on a scope (see the pics with a 1kHz modulation... which one is AM, which one FM?). I found out this is due to phase differences the analyzer cannot display.?
The SNA1 being a network analyzer (i.e. having a tracking generator) and a phase display I tried that, but it didn't work either, the generator not being locked to the carrier. It might work if I could tell the generator to remain at exactly the carrier frequency...?
So thats what prompted my initial question. Is there a variant of an SA capable of doing that, or a more or less sophisticated measurement setup?
cheers
Martin
<20230326_182203 _26.03.2023 - 18h22_.jpg>
<20230326_181913 _26.03.2023 - 18h19_.jpg>
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Re: Measuring Phase with an analogue spectrum analyzer?
This is a great question. The only difference between narrow band FM and AM spectrum (sine wave modulant) is the phase of the components.. There are a way to know if you have an AM or FM signal… .you must to use zero span and see the trace. Its little complex to explain in english for me but if you made the right settings the modulation sine wave will double the frequency when you are tuned at the carrier frequency …?
Regards, Patricio
Ing. Patricio A. Greco
Taller Aeronáutico de Reparación 1B-349
Organización de Mantenimiento?Aeronáutico de la Defensa OMAD-001
Laboratorio de Calibración ISO 17025?AREA: RF/MW?
Gral. Martín Rodríguez 2159
San Miguel (1663)
Buenos Aires
T: +5411-4455-2557
F: +5411-4032-0072
toggle quoted message
Show quoted text
On 28 Mar 2023, at 17:47, Martin via < musaeum@...> wrote:
Hi all,
do you know an analogue spectrum analyser able to measure phase?
The question came to my mind when playing with my freshly repaired W&G SNA1. I was looking at a 1MHz signal at various configurations of my signal generator in AM and FM. I started wondering how an AM spectrum is nearly identical to an FM spectrum although the signals are totally different on a scope (see the pics with a 1kHz modulation... which one is AM, which one FM?). I found out this is due to phase differences the analyzer cannot display.
The SNA1 being a network analyzer (i.e. having a tracking generator) and a phase display I tried that, but it didn't work either, the generator not being locked to the carrier. It might work if I could tell the generator to remain at exactly the carrier frequency...
So thats what prompted my initial question. Is there a variant of an SA capable of doing that, or a more or less sophisticated measurement setup?
cheers
Martin
<20230326_182203 _26.03.2023 - 18h22_.jpg>
<20230326_181913 _26.03.2023 - 18h19_.jpg>
|
Measuring Phase with an analogue spectrum analyzer?
Hi all, do you know an analogue spectrum analyser able to measure phase? The question came to my mind when playing with my freshly repaired W&G SNA1. I was looking at a 1MHz signal at various configurations of my signal generator in AM and FM. I started wondering how an AM spectrum is nearly identical to an FM spectrum although the signals are totally different on a scope (see the pics with a 1kHz modulation... which one is AM, which one FM?). I found out this is due to phase differences the analyzer cannot display. The SNA1 being a network analyzer (i.e. having a tracking generator) and a phase display I tried that, but it didn't work either, the generator not being locked to the carrier. It might work if I could tell the generator to remain at exactly the carrier frequency... So thats what prompted my initial question. Is there a variant of an SA capable of doing that, or a more or less sophisticated measurement setup? cheers Martin  
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Re: 8594E need documents for processor board and battery question
Gordon GM1THS?
?
I have two HP 8591E spectrum analysers one has the AA (wire leads) battery the other the coin cell type battery. The latter one is the easiest to replace it’s on a daughter board which has a super cap ( the one with the battery on the main board also had a super cap) so it’s easy to remove and as long as you have switched the spectrum analyser on for a half hour or so to make sure it’s charger up you will have no problem.?
?
Then??you just remove the daughter board then remove the plastic insulator under the board and remove the old battery and put in the new one. It’s best to back up the calibration data first to be sure tho. There was a spreadsheet template on the files section so you can put all the data in your spreadsheet I also updated the firmware to the last version I could find which was??980615 both my analysers were made in 1995 and had the original battery’s. The worst of the two replaced is the one with the battery on the main board as you have more to remove and the board interconnected was difficult to disconnect as you have to be careful not damaged the interconnect while removing the board.?
?
Gordon GM1THS?
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Re: looking for HP85101C display keys plastic frame
Many thanks again for your great support, Askild!
Best regards,
Tom
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HP 8656B A3 Low Frequency Loop Fractional-N Microprocessor
I have a faulty 8656B which is unable to establish a lock in the low frequency loop. There is no change at the output when troubleshooting with TP18 and TP17, which leads me to suspect A3U28 (HP PN 1820-3618) had failed. Serial data is seen at pin 9 of the IC and the 4MHz oscillator is working.
The chip looks like some sort of 8-bit Motorola micro, but I can't determine what type. Does anyone have any information on this chip or the firmware it is running?
Thanks and 73,
Ed
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8594E need documents for processor board and battery question
My HP 8594E has a serial number prefix of 3513
In the process of replacing the memory battery I discovered that my unit has the AA size 3.6 volt lithium battery installed directly on the processor/memory board.
The board is marked as:
Processor
A-3243-53
on a white sticker:
08590-60356
The 8590 series service manual I downloaded only has the newer set up with the battery on a sperate card.
In that manual it does have my board listed and refers to CLIP 08590-90254
I would like to obtain schematics and board layouts if anyone has them for this board. Have done some Googling, but no success.
Meanwhile, I have a question. Has anyone here replaced the battery on a unit that has the battery on the memory board like mine? If, so did you lift the board to unsolder the battery, or clip the leads and solder to the stubs, or unsolder and resolder from above without lifting the board?
Thanks
Rik
WA4BAN
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Re: HP 8594E low signal level indicated
Installed the 2nd converter and the 8594E is now indicating normal sensitivity.
Next up, is replacing the memory battery.
Rik
WA4BAN
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Patricio A. Greco
Dave McGuire
Martin
Sam Reaves
Rik Rasmussen WA4BAN