On 02/23/2018 11:15 AM, JM wrote:> On 21/02/2018 01:29, pcdhobbs@gmail.com wrote: >>> I have written a program that controls that thing over the network >>> and measures spectra from 0.1 Hz to 1MHz, one FFT per decade, reads >>> the results, combines them and plots them with gnuplot. >> >>> One needs a converter box from coax ethernet to contemporary network, >>> then one just opens port 5000-something on 192.168.178.111 and simply >>> reads and writes GPIB-strings. And the coax needs 2 terminations, even >>> when the "cable" is only 5 inch long. :-) >> >>> No need for GPIB cards and semi-supported drivers. >> >>> These measurements of voltage regulator noise have been done with it: >> < >> https://www.flickr.com/photos/137684711@N07/24070698809/in/album-72157662535945536/ >> >> > >> >> >>> Just in case you win it and are interested. >> >> Hi, Gerhard, >> >> I did, and I am. I'll have to gin up a nice low-1/f-noise preamp for >> it, but that'll be fun. >> >> Thanks >> >> Phil Hobbs >> > > Note that the software options can easily be unlocked on these (although > they would be of little use for your intended application).The cell-phone stuff won't help much, but I'm hoping that I can turn on the AYB (spectrogram and waterfall) option without scrooching it. (Option AY8, the internal source, would be useful too, but it's probably a HW option.) The software one should be no big issue as long as the floppy drive works reliably. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net https://hobbs-eo.com
FFT analyzer recommendations
Started by ●February 16, 2018
Reply by ●February 23, 20182018-02-23
Reply by ●February 23, 20182018-02-23
Am 23.02.2018 um 18:11 schrieb Phil Hobbs:> On 02/23/2018 11:15 AM, JM wrote: >> On 21/02/2018 01:29, pcdhobbs@gmail.com wrote: >>>> I have written a program that controls that thing over the network >>>> and measures spectra from 0.1 Hz to 1MHz, one FFT per decade, reads >>>> the results, combines them and plots them with gnuplot. >>> >>>> One needs a converter box from coax ethernet to contemporary network, >>>> then one just opens port 5000-something on 192.168.178.111 and simply >>>> reads and writes GPIB-strings. And the coax needs 2 terminations, even >>>> when the "cable" is only 5 inch long. :-) >>> >>>> No need for GPIB cards and semi-supported drivers. >>> >>>> These measurements of voltage regulator noise have been done with it: >>> < >>> https://www.flickr.com/photos/137684711@N07/24070698809/in/album-72157662535945536/ >>> >>> > >>> >>> >>>> Just in case you win it and are interested. >>> >>> Hi, Gerhard, >>> >>> I did, and I am. I'll have to gin up a nice low-1/f-noise preamp for >>> it, but that'll be fun. >>> >>> Thanks >>> >>> Phil Hobbs >>> >> >> Note that the software options can easily be unlocked on these (although >> they would be of little use for your intended application). > > The cell-phone stuff won't help much, but I'm hoping that I can turn on > the AYB (spectrogram and waterfall) option without scrooching it. > (Option AY8, the internal source, would be useful too, but it's probably > a HW option.) > > The software one should be no big issue as long as the floppy drive > works reliably.Mine has most options, but I'm not sure about the waterfall. What is missing is the source up converter for the RF section. But for RF I have a real VNA. That thing has so much parameters to set up that I wrote the program to control it remotely very soon. I had to use a pre-flight check list otherwise. Important options are dual channel, needed for cross correlation, source for Bode plots etc and memory extension. My program is in C, under Linux. It probably can be compiled under Windows, too. You'll need a lot of gain to mask the noise in the 1/f region. That eats into the dynamic range. I'll remove the most embarrassing FIXMEs over the weekend, a good opportunity to clean it up :-) cheers, Gerhard
Reply by ●February 23, 20182018-02-23
On 02/16/2018 09:59 AM, Phil Hobbs wrote:> Hi, all, > > I need another FFT analyzer. I really like my HP 35660A, but it only > goes up to 100 kHz (50 kHz for two-channel measurements). I'd really > like one that goes up to at least 10 MHz, and can do the same sorts of > stuff, especially display noise spectral density in different units on > different scales and perform frequency response testing easily. > > There are a bunch of USB-style things, which might be okay as long as > they have Linux software available. > > What I really want is a smallish boat anchor with two channels, 14-16 > bit resolution, > 50 MS/s sampling, FFT analysis, a nice display, and > that can talk to USB sticks.So my new-to-me HP 89441A analyzer is due to be here Tuesday. I noticed that it doesn't have the serial cable--is it a regular straight-through 9-pin cable, or something weird? Thanks Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net https://hobbs-eo.com
Reply by ●February 23, 20182018-02-23
On 02/23/2018 02:13 PM, Gerhard Hoffmann wrote:> Am 23.02.2018 um 18:11 schrieb Phil Hobbs: >> On 02/23/2018 11:15 AM, JM wrote: >>> On 21/02/2018 01:29, pcdhobbs@gmail.com wrote: >>>>> I have written a program that controls that thing over the network >>>>> and measures spectra from 0.1 Hz to 1MHz, one FFT per decade, reads >>>>> the results, combines them and plots them with gnuplot. >>>> >>>>> One needs a converter box from coax ethernet to contemporary network, >>>>> then one just opens port 5000-something on 192.168.178.111 and simply >>>>> reads and writes GPIB-strings. And the coax needs 2 terminations, even >>>>> when the "cable" is only 5 inch long. :-) >>>> >>>>> No need for GPIB cards and semi-supported drivers. >>>> >>>>> These measurements of voltage regulator noise have been done with it: >>>> < >>>> https://www.flickr.com/photos/137684711@N07/24070698809/in/album-72157662535945536/ >>>> >>>> >>>> > >>>> >>>> >>>>> Just in case you win it and are interested. >>>> >>>> Hi, Gerhard, >>>> >>>> I did, and I am. I'll have to gin up a nice low-1/f-noise preamp for >>>> it, but that'll be fun. >>>> >>>> Thanks >>>> >>>> Phil Hobbs >>>> >>> >>> Note that the software options can easily be unlocked on these (although >>> they would be of little use for your intended application). >> >> The cell-phone stuff won't help much, but I'm hoping that I can turn on >> the AYB (spectrogram and waterfall) option without scrooching it. >> (Option AY8, the internal source, would be useful too, but it's probably >> a HW option.) >> >> The software one should be no big issue as long as the floppy drive >> works reliably. > > Mine has most options, but I'm not sure about the waterfall. > What is missing is the source up converter for the RF section. > But for RF I have a real VNA. > > That thing has so much parameters to set up that I wrote the program > to control it remotely very soon. I had to use a pre-flight check list > otherwise. > > Important options are dual channel, needed for cross correlation, > source for Bode plots etc and memory extension. > > My program is in C, under Linux. It probably can be compiled under > Windows, too. You'll need a lot of gain to mask the noise in the 1/f > region. That eats into the dynamic range. > > I'll remove the most embarrassing FIXMEs over the weekend, a good > opportunity to clean it up :-) > > cheers, Gerhard > >Hi, Gerhard, Thanks, that would be great. We're an all-Linux shop round here, so no worries there. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net https://hobbs-eo.com
Reply by ●February 23, 20182018-02-23
Am 21.02.2018 um 02:29 schrieb pcdhobbs@gmail.com:> > I did, and I am. I'll have to gin up a nice low-1/f-noise preamp for it, but that'll be fun. >I'm working on a chopper preamp that should be flat down to at least 100mHz, but it seems that I cannot verify that with the 89441A. It works with parallel ADG819 analog switches, step up transformers, more low noise gain with ADA4898s on 500 KHz, synchronous demodulator back to baseband and some more gain. A Xilinx Coolrunner II generates the timing from a 100 MHz osc. It looks like I get 120 pV/rtHz. The main problem is the ringing of the step up transformer. I re-wired some Macom and Pulse SMD transformers under the microscope using 50u wire. That was no fun. 1/2 :-) cheers, Gerhard
Reply by ●February 23, 20182018-02-23
Am 23.02.2018 um 20:15 schrieb Phil Hobbs:> So my new-to-me HP 89441A analyzer is due to be here Tuesday. I noticed > that it doesn't have the serial cable--is it a regular straight-through > 9-pin cable, or something weird?I also had to make the cable myself. It wasn't much work, and it is known how to do it.
Reply by ●February 23, 20182018-02-23
On Fri, 23 Feb 2018 14:15:48 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:>On 02/16/2018 09:59 AM, Phil Hobbs wrote: >> Hi, all, >> >> I need another FFT analyzer.� I really like my HP 35660A, but it only >> goes up to 100 kHz (50 kHz for two-channel measurements).� I'd really >> like one that goes up to at least 10 MHz, and can do the same sorts of >> stuff, especially display noise spectral density in different units on >> different scales and perform frequency response testing easily. >> >> There are a bunch of USB-style things, which might be okay as long as >> they have Linux software available. >> >> What I really want is a smallish boat anchor with two channels, 14-16 >> bit resolution, > 50 MS/s sampling, FFT analysis, a nice display, and >> that can talk to USB sticks. > >So my new-to-me HP 89441A analyzer is due to be here Tuesday. I noticed >that it doesn't have the serial cable--is it a regular straight-through >9-pin cable, or something weird?The DOCs are online, if you don't have them. It appears to be a common serial cable (but who knows how many pins are used). There is also a comment about the EMI suppression ferrite position.
Reply by ●February 24, 20182018-02-24
On 02/23/2018 03:17 PM, Gerhard Hoffmann wrote:> Am 21.02.2018 um 02:29 schrieb pcdhobbs@gmail.com: > >> >> I did, and I am. I'll have to gin up a nice low-1/f-noise preamp for >> it, but that'll be fun. >> > > I'm working on a chopper preamp that should be flat down to at least > 100mHz, but it seems that I cannot verify that with the 89441A.I have a 35665A, whose 1/f is pretty good.> > It works with parallel ADG819 analog switches, step up transformers, > more low noise gain with ADA4898s on 500 KHz, synchronous demodulator > back to baseband and some more gain. > > A Xilinx Coolrunner II generates the timing from a 100 MHz osc. > It looks like I get 120 pV/rtHz.At 0.1 Hz? Awesome!> > The main problem is the ringing of the step up transformer. I re-wired > some Macom and Pulse SMD transformers under the microscope using 50u wire. > > That was no fun. 1/2 :-)I bet. I once spent about three weeks repairing metal-patterned PVDF pyroelectric films with silver paint for a customer demo, so I feel your pain. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Reply by ●February 24, 20182018-02-24
On 23/02/2018 17:11, Phil Hobbs wrote:> On 02/23/2018 11:15 AM, JM wrote: >> On 21/02/2018 01:29, pcdhobbs@gmail.com wrote: >>>> I have written a program that controls that thing over the network >>>> and measures spectra from 0.1 Hz to 1MHz, one FFT per decade, reads >>>> the results, combines them and plots them with gnuplot. >>> >>>> One needs a converter box from coax ethernet to contemporary network, >>>> then one just opens port 5000-something on 192.168.178.111 and simply >>>> reads and writes GPIB-strings. And the coax needs 2 terminations, even >>>> when the "cable" is only 5 inch long. :-) >>> >>>> No need for GPIB cards and semi-supported drivers. >>> >>>> These measurements of voltage regulator noise have been done with it: >>> < >>> https://www.flickr.com/photos/137684711@N07/24070698809/in/album-72157662535945536/ >>> >>> > >>> >>> >>>> Just in case you win it and are interested. >>> >>> Hi, Gerhard, >>> >>> I did, and I am. I'll have to gin up a nice low-1/f-noise preamp for >>> it, but that'll be fun. >>> >>> Thanks >>> >>> Phil Hobbs >>> >> >> Note that the software options can easily be unlocked on these (although >> they would be of little use for your intended application). > > The cell-phone stuff won't help much, but I'm hoping that I can turn on > the AYB (spectrogram and waterfall) option without scrooching it.You'll be able to do that.> (Option AY8, the internal source, would be useful too, but it's probably > a HW option.) >Oh, you got an 89431A as well as a 89410A? You'll soon be welding a couple of 42H racks on top of each other to save on floor space.> The software one should be no big issue as long as the floppy drive > works reliably. > > Cheers > > Phil Hobbs >
Reply by ●February 24, 20182018-02-24
On 02/24/2018 06:23 PM, JM wrote:> On 23/02/2018 17:11, Phil Hobbs wrote: >> On 02/23/2018 11:15 AM, JM wrote: >>> On 21/02/2018 01:29, pcdhobbs@gmail.com wrote: >>>>> I have written a program that controls that thing over the network >>>>> and measures spectra from 0.1 Hz to 1MHz, one FFT per decade, reads >>>>> the results, combines them and plots them with gnuplot. >>>> >>>>> One needs a converter box from coax ethernet to contemporary network, >>>>> then one just opens port 5000-something on 192.168.178.111 and simply >>>>> reads and writes GPIB-strings. And the coax needs 2 terminations, even >>>>> when the "cable" is only 5 inch long. :-) >>>> >>>>> No need for GPIB cards and semi-supported drivers. >>>> >>>>> These measurements of voltage regulator noise have been done with it: >>>> < >>>> https://www.flickr.com/photos/137684711@N07/24070698809/in/album-72157662535945536/ >>>> >>>> >>>> > >>>> >>>> >>>>> Just in case you win it and are interested. >>>> >>>> Hi, Gerhard, >>>> >>>> I did, and I am. I'll have to gin up a nice low-1/f-noise preamp for >>>> it, but that'll be fun. >>>> >>>> Thanks >>>> >>>> Phil Hobbs >>>> >>> >>> Note that the software options can easily be unlocked on these (although >>> they would be of little use for your intended application). >> >> The cell-phone stuff won't help much, but I'm hoping that I can turn on >> the AYB (spectrogram and waterfall) option without scrooching it. > > You'll be able to do that. > >> (Option AY8, the internal source, would be useful too, but it's probably >> a HW option.) >> > > Oh, you got an 89431A as well as a 89410A? You'll soon be welding a > couple of 42H racks on top of each other to save on floor space. > >> The software one should be no big issue as long as the floppy drive >> works reliably. >> >> Cheers >> >> Phil Hobbs >> >I got the complete 89441A 2.65 GHz gizmo. I'll move my spare Tek11801C out of the rack to make space. ;) You can fit a lot in a 7-foot EIA rack. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
