Recent Posts

1

Test Equipment / Re: Troubles with HP-8903B

« Last post by DeepLink on Today at 06:49:03 am »

I have several 8903B's and the internal oscillator is ~OK
Remember that you only have 5 digits on the frequency counter

Well, I did design a PLL to lock my 8903 to my house reference (10MHz)
Now the 8903 frequency counter is spot on, as it is directly linked to the reference
But the 8903 generator, is not locked to the internal oscillator, so it will never be precise (it is steered by the internal oscillator)
Not that it is needed for such an instrument

In loop back mode - you should see distortion below -90dB (0,003%) (look in the manual for how to perform the test)
I had one of mine down to -98dB (0,0012%)
I prefer dB for such low levels of distortion
You mention 150mA - but I guess you mean 150mV
Try to increase the output to 6V, 1kHz - then you should see distortion below -80dB (0,01%) if worse, then you instrument is faulty

Also the optional filters is not the best "quality"
So I did my own design with modern components and got the THD better
The filters is also hard to find these days

Also tried to improve the output generator / input circuit with modern Op-Amps and reducing noise in the supply's
Got some marginal gains
HP did make a pretty good Audio Analyzer, and it is my preferred analyzer.
It has "instant on" and is pretty simple to use, high voltage input and good bandwidth (I've measured them to more 500kHz)
If I need better performance I do have some modern FFT analyzers, but they all lack the above features

/Hans

2

Microcontrollers / Re: DS3231 RTC module huge drift

« Last post by retiredfeline on Today at 06:44:55 am »

There is no point trying to save battery by powering it with the main supply, the coin cell lasts a long time already. I have a couple of modules that have been running for a couple of years continuously. Some designs have a couple of diodes for dual supply if you are that fussy.

As I said, the I2C pins can be pulled up by the main supply, they are open drain so won't affect the RTC timekeeping.

3

Computers / Re: Format a 256GB pendrive with FAT32 using a windows 10 pc

« Last post by IanB on Today at 06:43:23 am »

Not sure if it's a GUI on top of command line tools or a GUI and command line tools on top of C/C++ libraries and APIs.

More or less the second one. Both GUI and command line tools call APIs to do their work.

4

Test Equipment / Re: Siglent SDS3000X HD and upgraded SDS1000X HD

« Last post by core on Today at 06:41:10 am »

I'm waiting for a teardown showing which FPGA and ADC are used in the SDS800X HD. The ADC converter seems to have the smaller capsule vs the SDS1000X HS, but the FPGA might be the same.

Indeed, it's a shame to waste resources, in the sense of not making full use of the ADC converter. 2 x 2GS/s would have made more sense.

If there were limits in the FPGA for example, it would have been logical and cheaper to use an ADC with 4 x 1GS/s channels in the same capsule.

However, we can still enjoy these devices considering the price/performance ratio.

5

Computers / Re: Format a 256GB pendrive with FAT32 using a windows 10 pc

« Last post by selcuk on Today at 06:38:31 am »

If you have a similar issue while formatting an SD card and found this topic, there is an official tool from SD card association:

https://www.sdcard.org/downloads/formatter/

6

Projects, Designs, and Technical Stuff / Re: (Yet Another) DIY Multislope ADC

« Last post by iMo on Today at 06:34:41 am »

..The project files are available, so it should be possible to get your own set of boards for experimentation, or replicate the core circuit (it's quite simple) on a breadboard..

Yep, the analog part of the design is an another story which we have not elaborated yet
My basic motivation has been to have a look at the 2040/PIO and its applicability. Of course it could be done by a stm32xxx (here we lack the PIO) or an fpga+MCU (here the complexity is higher) as well.
Hopefully rPi company will come with the rp2041 soon - with the fixed ADC, and with 4xPIO with 256 instructions each

7

Microcontrollers / Looking for information on TEST pin and ways to DUMP mask ROM of PIC1650 PIC16xx

« Last post by reverse on Today at 06:31:41 am »

Hi. Looking for information on TEST pin and ways to read out the mask firmware ROM on GI's (General Instruments) PIC1650  (PIC16xx) family of microcontrollers.

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Projects, Designs, and Technical Stuff / Re: Opamps - Die pictures

« Last post by Noopy on Today at 06:29:16 am »

Nice! Thank you very much! 
Would it be ok for you if I put your schematic on my website?

9

Computers / Re: Format a 256GB pendrive with FAT32 using a windows 10 pc

« Last post by magic on Today at 06:27:10 am »

Not sure if it's a GUI on top of command line tools or a GUI and command line tools on top of C/C++ libraries and APIs.

"GUI on top of command line tools" is how Linux Desktop stuff works, when it does

10

Test Equipment / Re: Standardised Way To Test Oscilloscope Screen Update Rate

« Last post by EEVblog on Today at 06:26:10 am »

I am thinking about the purpose of the refresh rate.
Perhaps the screen refresh rate is less important than the ability to display the waveform appropriately – so a waveform with a 'glitch' repeated at different rates could be used to test for this.

Yes, in theory the display refresh/update rate shouldn't matter if the scope is designed to or set up to capture the thing you are interested in. Persistance is one obvious way to do that for example.
But often you are just causally using you Mk1 eyeball probing around, in whcih case you don't want your fast waveform capture rate hindered by a slow display update rate.