Ezgpib

[jackinnj]

I am splitting this off from Glen's Audio Analyzer page --

I have been writing some routines for my HP Network Analyzer -- here's a link to the instruction set for the HP3577a:

http://www.tech-diy.com/TestEquipment/HP_Basic_Instr/HP_Basic.htm

 

[jackinnj]

Just a few minutes ago Prologix announced a LAN to GPIB adapter -- so you will be able to put your Tek or HP stuff on the web:

http://store.prologix.biz/gpiblan-controller.html

 

[jan.didden]

I got the test software for the Neutrik RT-1M speaking to the instrument over the GPIB yesterday.
Next step is to make EZGPIB to recognize it. I used EZGPIB_BusFindAllDevices but that failed to find the unit.

Jan Didden

 

[jan.didden]

OK, some progress.
Got EZGPIB to query the Neutrik and get status and ID back.
Then switched to RT-Eval which is a small evaluation utility, but fully functional, to load multitones in the unit and query the results.
Using an internal loop-back command I used a 30-tone multitone and got the attached for THD.


Jan Didden

 

[jackinnj]

I wrote a little program in ezGPIB to demonstrate the "correctness" of an RIAA preamplifier using the 3577a -- from the gain at 1kHz you set the zero. From the 20Hz and 20kHz extrema you set the limits. You can thus reset the vertical axis.

The Boonton 1120 and Tektronix AA5010/SG5010 are all programmable over the GPIB. Both the Boonton and Tek oscillators have THD% in the same order of magnitude as the AP system 2 (i.e. 0.0003% to 0.0004%). I would suggest that you can get a lot of performance with a lot less $$$ if you take the time to do a little programming with these instruments.

 

[jan.didden]

I wrote a little program in ezGPIB to demonstrate the "correctness" of an RIAA preamplifier using the 3577a -- from the gain at 1kHz you set the zero. From the 20Hz and 20kHz extrema you set the limits. You can thus reset the vertical axis.

The Boonton 1120 and Tektronix AA5010/SG5010 are all programmable over the GPIB. Both the Boonton and Tek oscillators have THD% in the same order of magnitude as the AP system 2 (i.e. 0.0003% to 0.0004%). I would suggest that you can get a lot of performance with a lot less $$$ if you take the time to do a little programming with these instruments.

Just bought a 3577A, to be delivered next week, tested, guaranteed and with full manual. As well as a Fluke System Multimeter 8520A. Also picked up an HP3437 System Voltmeter "as-is" which looked very good and clean and even had a cal sticker. I'll see if that works, a gamble for 45 euro.
I am slowly finding out that for a fraction of the cost one can put together a testbench that only big companies could afford 20-30 years ago.

I'd be interested in that 3577 RIAA program. I have no problems with EZGPIB's Pascal, been using Pascal in another life for a couple of years. I'm no geek but know my way around with it.

Have a nice and sunny weekend,

Jan Didden

 

[jan.didden]

Jack,

What do you use as input attenuator for the '3577A? Since the input headroom is quite limited, I'm currently using a 600ohms HP attenuator. Works well but it is only flat out to a few Mhz, and phase starts to roll of before that.

I was thinking to get a 50 ohms RF attenuator (there are many that are flat from DC upwards) but power handling is limited. I'd like to input up to 40 or 50VRMS from my power amps into the attenuator, but 50V is 50W in 50 ohms.

Any advice?

Jan Didden

 

[jackinnj]

sorry to get back late, i saw that this had lit up while i was away -- I use an HP 350D which, as you say, is only good to 1MHz or so, and is 600 ohms. I also have some attenuators which I built -- the "Curiously Refreshing 50 ohm attenuator" -- in Altoids tins -- I also have a rig to separate DC from the '3577.

I will publish the RIAA program, but it is pretty simple..

I am not worthy to secure the sandle-strap of any of those guys on the HP Microwave Forum at Yahoo. The best I ever did was 1296 MHz.