Recent Posts

1

Test Equipment / Re: Hacking the Rigol DHO800/900 Scope

« Last post by PELL on Today at 06:41:28 am »

Haven't been around here quite a time, very glad to see you guys are still working on this scope

I had talked with someone who used to work at Rigol HQ, and he told me: "The PS part of that 7015 isn't used at all, we only use PL for the work". This might be a rumor, but depends on you.

You might ask why not use an Artix or Spartan if they don't use the PS part. I guess that's because those lower-end ZYNQ chips are incredibly cheap in China right now, I am talking about $1 ZYNQ-7010/pcs or $6~7 ZYNQ-7020/pcs (of course not brand new, it is second-hand but tested to make sure it is functional) at online sales.

Rigol certainly did use brand-new chips, but from the example above, you can imagine how cheap if you purchase a bunch of them from Xilinx.

 

2

Computers / Re: Australian Government Invests $1BN on Aussie Quantum Computing Startup

« Last post by Whales on Today at 06:38:12 am »

Australia will invest $940 million in Silicon Valley start-up PsiQuantum in a major bet that it will build the world’s first commercially useful quantum computer in Brisbane.

Is there any evidence of a quantum computer doing anything better than a traditional computer, or is it just all theoretical?

For fun see page 203 of the 2024 Sigbovik : "Quantum Disadvantage.  Or, simulating IBM's 'quantum utility' experiment with a Commodore 64"

3

Test Equipment / Re: Looking for a "SeamSeamless Data Logging" / "Continues recording" osciloscope

« Last post by Someone on Today at 06:29:35 am »

(Expensive enterprise special case test equipment scope solutions are also intereting and welcome on this thread)

You are describing a "digitiser" not a scope. The primary/distinguishing feature of a scope is triggering.

4

Repair / Re: IWATSU oscilloscope Cal signal square wave showing as ramped / curved signal

« Last post by 2N3055 on Today at 06:27:29 am »

This (4901-2) is supposed to be a compatible probe to the original iwatsu ss-0060; it's not clear to me how different this is than the lecroy PP002 I tried is.

The Probemaster 4901 has a compensation range of 10-50pF, meaning it will work on scopes with up to 50pF input capacitance.  IDK what the input capacitance is on your Iwatsu, but it may be higher than the maximum compensation available with that LeCroy probe.  Or, it may be broken.

That Iwatsu has 32pf±2pF input capacitance.  That fast LeCroy 14pF probe probably cannot be compensated.

5

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

« Last post by tautech on Today at 06:27:14 am »

The new to come 6&8 GHz models ?

First time I see BW references inside Siglent's FW going up to 16GHz !!!

This means, any 20..40Gs gear to come. Than we go with Bodnarpulse to the real 30ps risetime 

Requires any better based oscillator & synthesizers as in fs... just look at LeCroy HD series. To get any trusted Jitter figures.

Already available. 
https://siglentna.com/product/precision-frequency-reference/

6

Repair / Datasheet for Nichicon SE series ?

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

I'm checking some caps in an older stereo from the 1980's, and I can't find much info on Nichicon SE(M) series caps, they are typical looking radial leaded electrolytic's, only 85C rated.

What's similar to them, what table or datsheets might I use to check their dissipation factor or ESR ?

7

Projects, Designs, and Technical Stuff / Re: RP2040 or RPi as data logger

« Last post by darkspr1te on Today at 06:21:08 am »

If you are looking for something already spun up then look for the "better picoboard" ,
it has sd built in along with some nice improvements over original board and yet is the same size.
There is also the Adafruit Picowbell logger which has a few more bells and wifi.


on github there is a neat bootloader that shows sdcard when plugged into pc and if you hold the bootkey it will go into dfu mode , firmware can also be pulled from sdcard in the next boot then renamed when done.


i think it was called pico-tool , i will have to check.


darkspr1te

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

« Last post by hpw on Today at 06:19:03 am »

The new to come 6&8 GHz models ?

First time I see BW references inside Siglent's FW going up to 16GHz !!!

This means, any 20..40Gs gear to come. Than we go with Bodnarpulse to the real 30ps risetime 

Requires any better based oscillator & synthesizers as in fs... just look at LeCroy HD series. To get any trusted Jitter figures.

9

Test Equipment / Re: Hacking the Rigol DHO800/900 Scope

« Last post by aXit on Today at 06:16:30 am »

Looking at the zynq 7015 pinouts along with the board layout gives some clues to the DDR SDRAM usage.

The DDR3L chip on the DHO800 is connected up to bank 13 (yellow), this will be a DDR memory controller implemented in the FPGA fabric. The gigadevice GDP2BFLM-CA is a 16-bit wide, 2133MT/s device, if clocked at it's rated frequency, that gives 34GB/s theoretical memory bandwidth.

It looks like bank 35 (magenta) is being used for the ADC interface, 1.25Gsps @ 12-bit is 15GB/s. Considering the memory is 16-bit wide, and there are also 16 logic analyser inputs, they could just be storing 12-bit samples as 16-bit instead of repacking, bringing the ADC sample bandwidth up to 20GB/s.

I'm assuming that bank 34 is mostly being used for the differential LA inputs, as well as any other GPIOs/controls (based on some visible single ended signals on the top layer here too).

Bank 112 (blue) are the GTP tranceivers implementing the PCIe device on the RK3399.

The DHO800 unpopulated memory devices (orange) are specifically for the PS / ARM SoC part of the zynq chip. In most zynq applications, this memory would be the system memory for embedded linux running on the PS. In these situations, any high bandwidth data needs to pass from the FPGA fabric (PL) to the PS via some dedicated  AXI buses inside the zynq, and then handled by the PS memory controller, on a separate clock domain. While they technically have the bandwidth (4x buses of 8-16GB/s, depending on clocks), it's likely that just having a synchronous memory device directly on the FPGA fabric is much more suitable for continuously streaming data from an ADC.

It's not clear to be what the PS is being used for in this zynq. Clearly it's not running embedded linux, since the RK3399 is running the host OS, and there's no system memory on the DHO800 series. It could be running some RTOS doing doing measurements, stats or monitoring (with the limited 256KB of on-chip memory available to it), but I really have no idea.

10

Test Equipment / Re: Looking for a "SeamSeamless Data Logging" / "Continues recording" osciloscope

« Last post by tautech on Today at 06:15:13 am »

I was using Lecroy oscilloscopes with Pass/Fail or Mask in order to automate the capture of signals, I was able to log thousands of captures and storage them in the Osci HDD or Externally, also possible to save the waveforms. Would be interesting to see how often it can capture due to possible buffers and so on.... I did not check, but might be an idea.

Any other oscilloscope with these kinds of functions might work, for sure you will need to think about how to automate or which criteria to use.

I know it is not a "cheap" solution at least on these "high end" oscilloscopes but as said, as an idea.

LeCroy is not the only brand that offers a good Pass/Fail feature. 

Eg, with a $500 DSO:
https://www.eevblog.com/forum/testgear/sds800x-hd-review-demonstration-thread/msg5480482/#msg5480482