Recent Posts

11

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

« Last post by Bud on Today at 04:45:32 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.

The ICOM radios had a receiver.  They could receive a broadcast transmission to detonate.  This broadcast signal could potentially be transmitted from an overhead Israeli drone.

This is a fantasy. Radios would need to be turned on and tuned to a specific frequency and specific operating mode. No reasonable attacker would rely on such vage conditions for a success.

12

Beginners / Re: Amscope trinocular microscope and Eakins camera issues

« Last post by Psi on Today at 04:40:53 am »

Yeah, i dunno why everyone sells this microscope in this config, you need the lens on the trinocular port

13

Projects, Designs, and Technical Stuff / Re: Balanced line level input for PCM1804 without negative supply

« Last post by MasterT on Today at 04:40:49 am »

>>> Is rail-to-rail really necessary?

 Nice to have, R2R otput of the OPA greatly simplify interfacing, because when Vcc of the ADC and Vcc of the OPA is the same you don't care about adc input protection against higher voltage presents. They used 47 Ohms (PCM1804 data sheet) for double purposes, as filter & OCP / OVP. Resistor at adc inputs creates non-linearity and THD , so value can't be too high, same time with +15V input injected current may reach ~200 (!) mA or whatever OPA can source.

>>> If the input approaches the supply rails then I think the signal will already be clipping, and it shouldn't reach this with line level signals.

 Depends on opa, this is why "zerocross" was introduced. Get DS of tlv2365 and check input offset voltage vs Common Mode voltage.
THS73xx series has gain x2, so input CM is not an issue.

>>> So is buffering the input lines directly a good topology? What are some criteria I should like out for when picking an op-amp for this application, and what circuit should I use (filtering and such)?

  If 10k impedance at the entry point is ok than inverting topology simplify OPA selection. For high inpedance (100k-10Mohm) non-inverting topology of course. Using tlv2365 gain x1 (follower) is possible, for others OPA gain >2 required to limit inputs voltage.

14

Beginners / Re: Amscope trinocular microscope and Eakins camera issues

« Last post by newtekuser on Today at 04:36:17 am »

I can confirm that the reduction lens solves my issue.

15

General Technical Chat / Re: Why does the US provide all critical electronic design knowledge to the world?

« Last post by Andy Chee on Today at 04:34:04 am »

As for poor SNR, perhaps it's time to upgrade your receiver with a better noise filter?

The problem is with the transmission, not the reception.

You're correct.  Your choice of transmission frequency (i.e. font color) has low SNR and is difficult to detect from the background.

16

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

« Last post by shabaz on Today at 04:21:34 am »

Interesting. I missed that diagram, I believe it must be correct, but I'm wondering if the result will be benign because after the averaging operation the value is converted back into the normal dBm power scale, so if averaging number is set to 1 (if possible) or disabled, then the result shouldn't change. But I'm really not sure. Maybe it does have an impact on other averaging that occurs in-between.
I looked at an R&S user manual and it positions those settings in the trace averaging menu, but that may just be a logical rather than physical placement.

Definitely worth a test. I just now quickly tried on a Keysight SA, I couldn't tell the difference when the trace average was off, but I only fed a sine-wave. I could try some more interesting signals tomorrow perhaps, and just eyeball if any difference is seen, admittedly it's not a very certain method.

17

Test Equipment / Re: ngscopeclient - Ultimate acquisition software / protocol decoder / debug tool ?

« Last post by azonenberg on Today at 04:15:08 am »

Hi, I don't have drive D in my computer. Also /Home/fborry is not from me.

Yeah that's the path of the source file (see "imgui__draw.cpp, line 2583" in your screenshot) on my build environnement (this is a debug build), not to be confused with the path to look the fonts for.
Maybe try and remove or rename your preferences.yml file and launch the installed ngscopeclient, it should fix the problem.

Ok, that was. Removing preferences.yml has allowed the installed version to launch. Now both instances can be launched.
Thank you!

Yep you got hit by https://github.com/ngscopeclient/scopehal-apps/issues/707. We don't have a root cause but there's a fairly straightforward workaround we can do to at least avoid a crash when it happens. But there's a million other things I'm juggling and this one hasn't got to the top of the stack.

18

Test Equipment / Re: ngscopeclient - Ultimate acquisition software / protocol decoder / debug tool ?

« Last post by azonenberg on Today at 04:13:08 am »

We can do FFTs on input from any supported scope.

The FFT filter outputs only the FFT of the current input, but there are separate filters for peak holding and exponential moving average that can be applied to the output spectrum which in combination should give the behavior you want, I think.

19

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

« Last post by Postal2 on Today at 04:10:29 am »

.....Also, good to see that I'm not the only one that uses an ancient version of the browser

I use these files to watch youtube on Windows XP computers, I don't know a simpler and more reliable way. Yes, these files automatically replace useragent when accessing youtube and contain modern codecs. I have Windows 10 computers, but I find it extremely inconvenient to work with them.

You can transfer data via COM at 921600 for a month, and Windows XP will not fail. For some reason, Windows 10 cannot do this, I did not succeed. Probably, Windows 10 can even reboot in the process, I do not want to find out.

20

General Technical Chat / Re: What do you WANT to buy?

« Last post by brucehoult on Today at 04:08:34 am »

I want to buy a board based on the Sophon SG2380 SoC, which should leapfrog the Arm A76 based boards such as the Raspberry Pi 5 and RK3588 boards such as Rock 5 and Orange Pi 5.

Hopefully H1 2025...