Nice video, thank you. Just one question which I can't get to have answered: How would I test a wired mouse (whose usb cable is detachable) for precompliance? -Do I need a LISN or can I do simply with the RIGOL SA and a near field EMI sniffer probe? - If I need a LISN, how do I connect the USB cable of a wired mouse to it? Ty
I have had similar scenario (not a mouse but a USB connected device with removable cable). The testing lab used a "golden" laptop that they knew would pass the line conducted test. First they tested the golden laptop by itself (it passed) and then they added the USB device and retested (it passed again). This is a pretty common procedure. I used to work for a company that developed laptop accessories and this is the same thing we did. We would find a laptop that passed and then hung on to it and used it for all subsequent testing. Had an instance where our golden laptop no longer passed and found that the hard drive and been replaced. We went back to the old hard drive and the laptop once again passed the line conducted test :) So yes, IMO, you need a LISN. Mouse plugged into computer and that computer is plugged into LISN.
@@DanPattenAudioG33k awesome story. Thanks for the response, very helpful. So I guess, no precompliance I can do at home on the PCB of the mouse, without it connecting to a golden computer and without visiting/paying for a test lab?
You can do pre-compliance for your product outside of the lab provided you have the proper equipment. For FCC compliance, your prime concerns are conducted and radiated emissions. Conducted is pretty easy with spectrum analyzer (SA) and LISN. Radiated is more difficult but you can get an indicator using an SA and TEM cell (possibly with shielding bag).
Dear Dan, great video! Remind that's rather dangerous to load the LISN with the SA connected. Also switching between phases can cause very high signals at the SA input. I'll suggest to disconnect the SA fron the LISN when loading the LISN and switching between phases. The beeps indicate that the input level of the SA is too much. Otherwise: thumbs up, great video!
I hate to admit it but I blew the front end of a SA when a PSU blew up while on the LISN. I was always much more careful after that, even unplugging SA input when powering up.
Sorry about old reply :) I agree, a good practice would be disconnecting SA while switching phases and DUT. My LISN used in this video has a built-in transient limiter that I was relying on. I ALWAYS use a transient limiter when using a LISN connected to my spectrum analyzer. When I use this LISN I use the built-in transient limiter. I also use an old Hewlett Packard 11947A (no longer manufactured I believe) or the nice Tekbox TBFL1 www.tekbox.com/product/tekbox-tbfl1-transient-limiter/
@@DanPattenAudioG33k A transient limiter contains usually some sort of diode. The disadvantage of semiconductors is that they can create wideband noise and 'mess up' the measurement. A limiter does work for protection, but beware (especially in high RF level conditions) that the measurement can be affected. The measurement will appear worse then the real signal due to the added RF components. Just a thought. ;-)
Yeah agreed here. The FLIR and other ones may still pass, but would have been interesting to see them loaded up, as being unloaded it's possible in hardware to make the power supply virtually "off" until a minimum load is detected and connected.
Good point. I should have shown the tests without load and possibly different amounts of load. In general the adapters that did not pass unloaded, also failed when loaded.
i am learning from you....Thank you for making these videos
Your welcome. Glad it has helped.
@@DanPattenAudioG33k ua-cam.com/video/HyNF4bEu60Q/v-deo.html
Nice video, thank you.
Just one question which I can't get to have answered: How would I test a wired mouse (whose usb cable is detachable) for precompliance?
-Do I need a LISN or can I do simply with the RIGOL SA and a near field EMI sniffer probe?
- If I need a LISN, how do I connect the USB cable of a wired mouse to it?
Ty
I have had similar scenario (not a mouse but a USB connected device with removable cable). The testing lab used a "golden" laptop that they knew would pass the line conducted test. First they tested the golden laptop by itself (it passed) and then they added the USB device and retested (it passed again). This is a pretty common procedure.
I used to work for a company that developed laptop accessories and this is the same thing we did. We would find a laptop that passed and then hung on to it and used it for all subsequent testing. Had an instance where our golden laptop no longer passed and found that the hard drive and been replaced. We went back to the old hard drive and the laptop once again passed the line conducted test :)
So yes, IMO, you need a LISN. Mouse plugged into computer and that computer is plugged into LISN.
@@DanPattenAudioG33k awesome story. Thanks for the response, very helpful.
So I guess, no precompliance I can do at home on the PCB of the mouse, without it connecting to a golden computer and without visiting/paying for a test lab?
You can do pre-compliance for your product outside of the lab provided you have the proper equipment. For FCC compliance, your prime concerns are conducted and radiated emissions. Conducted is pretty easy with spectrum analyzer (SA) and LISN. Radiated is more difficult but you can get an indicator using an SA and TEM cell (possibly with shielding bag).
@@DanPattenAudioG33k thank you Dan :)
@@rockndancenroll Your welcome. If you need help and your only looking for a couple of measurements, I can help you out.
Dear Dan, great video! Remind that's rather dangerous to load the LISN with the SA connected. Also switching between phases can cause very high signals at the SA input. I'll suggest to disconnect the SA fron the LISN when loading the LISN and switching between phases. The beeps indicate that the input level of the SA is too much. Otherwise: thumbs up, great video!
I hate to admit it but I blew the front end of a SA when a PSU blew up while on the LISN. I was always much more careful after that, even unplugging SA input when powering up.
Sorry about old reply :) I agree, a good practice would be disconnecting SA while switching phases and DUT. My LISN used in this video has a built-in transient limiter that I was relying on. I ALWAYS use a transient limiter when using a LISN connected to my spectrum analyzer. When I use this LISN I use the built-in transient limiter. I also use an old Hewlett Packard 11947A (no longer manufactured I believe) or the nice Tekbox TBFL1 www.tekbox.com/product/tekbox-tbfl1-transient-limiter/
Sorry to hear. When ever I am doing a direct connected measurement, I always insert a transient limiter.
@@DanPattenAudioG33k A transient limiter contains usually some sort of diode. The disadvantage of semiconductors is that they can create wideband noise and 'mess up' the measurement. A limiter does work for protection, but beware (especially in high RF level conditions) that the measurement can be affected. The measurement will appear worse then the real signal due to the added RF components. Just a thought. ;-)
Hello Dan,
Why didn't you loaded those chargers with nominal maximum output current during tests?
Yeah agreed here. The FLIR and other ones may still pass, but would have been interesting to see them loaded up, as being unloaded it's possible in hardware to make the power supply virtually "off" until a minimum load is detected and connected.
Good point. I should have shown the tests without load and possibly different amounts of load. In general the adapters that did not pass unloaded, also failed when loaded.