Products > Test Equipment
Agilent E4432b unlevel issue again
hackwell:
I lost my cal data because I changed the model from E4432 to E4433 via GPIB so now the flatness is out of range around 1.8GHz.
That's why I need to reflash the memories. Not a big deal , but I'm still left with my initial issue. It seems the SHF0189 have less gain than the original amplifiers from Agilent so the signal is 5dBm lower thant it should be.
I had to replace 4 of them to get rid of the unlevel error ! 2 of them were utterly shorted to ground and the 2 others have turned into attenuators...
I had a look at the calibration procedure and it's quite tricky. It requires a bunch of test equipment I dont have , all connected to the computer via HPIB and it sort of auto calibrate by retrieving the measured values from the measuring gear and write the calibration data straight into the generator without telling you what's it's really doing >:( pretty well secured process. Plus some of the test gear needed have to be the exact model mentioned in the service manual. Well...
Has somebody already done that?
But I discovered some intersting things:
-The IQ calibration fails with a 517 error with no further information. But the modulation works fine so it must be relate to the amplifier gain lack. But you can perform a manual calibration and specify a range of frequencies. Tried this with various values and it only fails from 9KHz to 1.5 Ghz and passes from 1.5GHz to 4GHz. I still don't know why tho.
-There is a 93C66 EEPROM on the output board. Apparently it holds some configuation data abt the board model. As I said I have 2 models of output boards. One with the 1GG7 4235 amplifiers with a bypassed IQ modulator and one with the SHF0189.
The synthesizer board doesn't sweep at the same frequency range depending on the output board!! one from 1.5GHz to 2 GHz at -10dBm and the other from 1GHz to 1.5GHz then then jumps to over 3GHz at 0dBm ( I can't see that because my SA only goes up to 2.9GHz ) weird enough!
I wonder what will happen if I swap those 2 EEPROMS ? I have to try this.
-Played a bit with the LF generator and it's a pretty cool stuff. Nearly a full loaded func gen with many waveform choices and a frequency range from DC to 10KHz.
--- Quote from: TheSteve on May 27, 2019, 09:37:39 pm ---
I still want to know the location of the lower end frequency. I believe they should operate down to 9 kHz.
--- End quote ---
I'm not sure it would , as the SHF0189 have poor low freq performance. I'm still trying to hack the firmware tho. What about using the LF gen?
hackwell:
I just reflashed U107 and U106 with their original contents. My calibration data are back. The unit complained about a corrupted RAM content on the first boot but everything OK after rebooting.
The calibration data seem to be stored inside U107 at addresses from $40 to $8C and are blanked out to $FF if you change the model number via GPIB.
U106 showed many differences at various addresses too , I'm trying to figure out what they're related to.
here are some differences :
--- Code: ---address before after
$40 15 38 40 70 00 01 40 40 74 10
$BC FF FF 2A C8 40 70 FF FF 2E B0 50 74
$DA 55 48 15 38 7F 80 41 34 11 40 6F 84
$57A 7F 9C F6 A7
£581 28 35 76 28 36 7C
$5DB FF FF 7F B4 35 5E FF FF F6 8F 36 54
$5FC 7F B4 4A EA F6 8F C0 DB
$602 35 5E 36 54
$43BE 83 C2 C2 D4
$43C5 33 FF FF 34 00 32
$43D1 E6 5A 0B C0 ED CD 65 00
$4410 40 A7 70 2E 07 FF FF FF 40 AF 40 2E 08 00 00 60
$4468 40 A7 70 2E 07 FF FF FF 40 AF 40 2E 08 00 00 60
--- End code ---
and many other locations were affected too.
TheSteve:
Colby let me know that the low frequency limit is at CAL 165,1. I lowered mine to 9 kHz but it had no output that low. It had output from 30 kHz and above but it was not a clean usable signal. I wouldn't go below 50 kHz and even that might be suspect and needs further verification.
hackwell:
It's not surprising. As I said the RF amplifiers along the signal path have bad performances at low frequencies.
I tried many things to get the ouptut level of my set withing specs to no avail.
So the next step is to get the calibration software running and see what happens.
Not sure at all it would work with my National Instruments USB GPIB instrface tho
Ordinaryman1971:
I have two questions about ESG signal generators.
First one is...:
I have a 1GHz version of ESG... E4400... which was working fine.
I've bought a second one 2GHz version with bad screen. I've decided to test it with the good screen from 1GHz one and installed it in the 2GHz one... the screen stopped working.
Now I have two signal generators with not working screens. The screens are both fully turned on, all the pixels are black.
I can hear either one of them turning on and clicking relays but I can't display anything on either screen.
Any experience with problem like this. Not sure how to approach it.
Did I burn the second screen and how did I do it.....
Is there any way to monitor the output out of signal gen and see if there is anything out of it.
Second question is:
I just bought another ESG yesterday... 4GHz version and it's turning on, the display is working fine but I get two errors;
513, 1GHz oscillator unlocked
521, YO loop unlocked.
I've measured the output of the refference and it's 9.9981kHz... well 20Hz out, the signal is peaking at 2.7V
I've connected external refference... (oxco) and I'm getting the same errors.
Where is the 1GHz refference coming from... is it refference board or some other place.
Is it a refference board that's bad?
If I will be able to fix either.. all of them, wanted to give it a chance and possibly hack it to higher frequency.
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