Recent Posts

1

Test Equipment / Re: DG4000 - a firmware investigation

« Last post by Blanc on Today at 01:51:30 am »

Hello everyone.

Thank you very much for your supports and advices.
Last night, I found a USB memory that can refresh the FW of DG4000 among a lot of old USB memories.
After perusing this thread, I managed to get the latest "well tuned" DG4000 :-).
During the FW update, I was frightened by the lights of buttons turning on and off many times.
I made two mistakes along the way.

This morning, I calibrated the DG4000 again.
The attached photos are the conclusion.I set the AWG 50 ohm output, 1kHz.
Then I increased the amplitude in steps starting from -56dBm.
You can see abnormal rises and falls in the amplitude.
This symptom only occurs on ch1. I think this is evidence of a hardware failure in ch1.

I understand that the DG4000 is a hobbyist device, not a professional device,
and the amplitude of the AC frequency is sensitive and affected by various environmental conditions.
I think the photo shows the discontinuous of amplitude exceeds what would be the case in such conditions.

2

Microcontrollers / Re: Mircro-controller designs to generate nano second pulses with variable delay.

« Last post by PCB.Wiz on Today at 01:50:43 am »

The "thing" I am trying to control are MOSFET gate drivers of switching circuit I am trying to build.

Some more thoughts on this :
If the clock-sampling jitter on the trigger pulse is a problem, a hybrid solution might work.
Use chained monostables for the immediate 'close in' two output pulses, will give you sub-ns jitter and analog precision of delays and widths.
Then, the further out pulses, of 1us+ are probably ok with clock based pulses. The % error is quite small of 7ns in 1us

3

Repair / Re: Tektronix TDS 820

« Last post by lordium on Today at 01:45:52 am »

I recently just happened to buy one of these TDS820 for some testing. I did a backup of the firmware and nvram (v2.03e) and unlocked the FFT (option 2F). I attach here if anyone needs in the future.

Unlock option 2F (FFT):
unlock nvram switch on side first, send commands over gpib, then lock, reboot, done

PASSWORD PITBULL
WORDCONSTANT:ATPUT 327689,1

commands I used to get the firmware/nvram:
./tektool -r NVRAM_all.bin -b 0x04000000 -l 0x100000
./tektool -r firmware.bin -b 0x01000000 -l 0x400000

4

Projects, Designs, and Technical Stuff / Re: LAB techniuque to avoid higher current then possible

« Last post by NiHaoMike on Today at 01:45:07 am »

I'm not understanding the problem, the TL431 cannot supply any current, it can only sink it. The current supply is from the opamp which is limited by the resistor.

5

General Technical Chat / Re: What did you buy today? Post your latest purchase!

« Last post by DaneLaw on Today at 01:44:30 am »

A Chinese gadget--
Taken the family & friends with fondness '
Based on a triggered electromagnet.

6

Test Equipment / Re: Trying to use frequency counter to read WFM/s from MSO5000. Need help.

« Last post by Sensorcat on Today at 01:43:10 am »

Use the frequency measurement from the measurement menu instead. It offers several parameters to customize the measurement and address the issues you see with the counter. This includes the possibility to average, which is useful because you don't want the peak rate, as Someone pointed out. But it's definitely possible to measure this with the instrument itself. I have done that, at least for some instrument settings.

7

General Technical Chat / Re: Possible to trigger at battery explosions in pagers ?

« Last post by Bud on Today at 01:33:18 am »

And the pagers blew up around the country, so they must have found a way to send the trigger message using Hezbollah's transmitters infrastructure.  Or how could they transmit the trigger message over such a large area?

By using a programmed timer. No need to hack the infrastructure. The ICOM radios did not have a transmitting infrastructure, yet still blew up.

8

Test Equipment / Re: What does "Average Type" Refer To in Siglent SVA1032X "BW" Menu ???

« Last post by Someone on Today at 01:32:03 am »

Because as has been made clear here many times, it's not the "Trace Type" in the Trace menu, and it is not the "Average" settings in the Detect menu.

Average detector can use several different "laws", which are selected in the BW menu on these instruments. Where is the confusion?

Do you have any evidence of the result being affected when you change the BW averaging type while the detector is set to the Pos Peak, Neg Peak, or Sample modes ?

9

Test Equipment / Re: Trying to use frequency counter to read WFM/s from MSO5000. Need help.

« Last post by ballsystemlord on Today at 01:31:28 am »

You really need another scope to check the "trigger" (acquisition) out waveform. It is usually pluse trains with inconsistent frequency, that will confuse many "frequency" measurements, and unscrupulous manufacturers use the peak rate of the pulses as their spec.

When setting the "Gate time" of my DMM I did notice that. I've seen others, on YT, use dedicated frequency counters to do the same measurement I'm doing with my DMM. So, I assumed my DMM was good enough for the job.

Unfortunately, I have only one oscilloscope at this time. Although I could go for one of those really cheap handheld scopes from china, I think I'm better off waiting till I could afford better equipment.

10

General Technical Chat / Re: Some YouTube videos glitching for no reason.

« Last post by BillyO on Today at 01:30:46 am »

Nothing to do with Firefox.  I have had the same problems with various versions of Chrome.

It's just YT - "F'ck you, we don't care, and no, there is no way to tell us about it. We don't want to hear about it.  We have billions of customers and billions of dollars, so YOU don't matter .. bend over and like it or lump it .. now, agan, f'ck off!!"

I have a small YT channel and 5 years ago I was making more money than I am now even though I have about 3 times more views and subscribers.  It would be great if here was a competitive alternative.