Search found 561 matches

by Pito
Sat Feb 25, 2017 5:34 pm
Forum: General discussion
Topic: 1024 point fft - results not as expected
Replies: 5
Views: 130

Re: 1024 point fft - results not as expected

I would start with finetuning of the basics - your measurement setup. You have got there several sources of noise. 1. Sensor and cables (ie 50-60Hz hum and its multiplies, noise from the electromotor) 2. adc sampling jitter (where the sampling actually starts) 3. measurement loop timing jitter (micr...
by Pito
Fri Feb 24, 2017 12:18 pm
Forum: General discussion
Topic: 1024 point fft - results not as expected
Replies: 5
Views: 130

Re: 1024 point fft - results not as expected

Multiplying real and imag by 16 has no effect, imho. To achieve better amplitude precision of the spectra you must make several FFTs and average them. I think the precision (of random noise-like-signals) is related to 1/sqrt(N), where N is number of spectra averaged. To get 1% precision you need 100...
by Pito
Fri Feb 24, 2017 6:41 am
Forum: STLink
Topic: ST-LINK V2-1 does not work with Windows 10
Replies: 9
Views: 129

Re: ST-LINK V2-1 does not work with Windows 10

And what about zadig_2.2?
by Pito
Thu Feb 23, 2017 9:10 pm
Forum: STM32F4 Boards
Topic: STM32 ST-Link "no target connected" Error
Replies: 9
Views: 4637

Re: STM32 ST-Link "no target connected" Error

When you see the message then unplug/plugin the stlink dongle. Do not change the usb port. It may find the stlink then.
by Pito
Thu Feb 23, 2017 9:01 pm
Forum: STLink
Topic: ST-LINK V2-1 does not work with Windows 10
Replies: 9
Views: 129

Re: ST-LINK V2-1 does not work with Windows 10

When you see the message try to unplug and then plug-in back the stlink-dongle (do not change the usb port).
It helped in win7 thus it may help with win10 too..
by Pito
Tue Feb 21, 2017 3:33 pm
Forum: General discussion
Topic: 1024 point fft - results not as expected
Replies: 5
Views: 130

Re: 1024 point fft - results not as expected

The spectra you get is a garbage. Something fundamentally wrong there. I think the fill and real_to_complex functions are wrong. Do it simply such you fill the 32bit sample value (16b_imaginary+16b_real) while you generate the wave. All the signal samples must be 32-bit data containing the 16-bit re...
by Pito
Sat Feb 18, 2017 8:30 pm
Forum: Postbag
Topic: Rogers postbag - FM radio band transmitter
Replies: 35
Views: 471

Re: Rogers postbag - FM radio band transmitter

You need a better wire and solder iron. The soldering job above could introduce shorts..
There should be the i2c pull-ups on the board already assuming the chip needs to be programmed to work..
by Pito
Sat Feb 18, 2017 1:01 pm
Forum: Libraries & Hardware
Topic: SDFat library - how to get work parseInt() ?
Replies: 11
Views: 139

Re: SDFat library - how to get work parseInt() ?

What does it mean "code does not work" ?? Do not try to mess with complex sketches, instead try to go step-by-step. Try the original example (my above code snippet is from) from the SdFat until it works perfectly. And after then you may play with the code. https://github.com/greiman/SdFat/...
by Pito
Sat Feb 18, 2017 11:14 am
Forum: Off topic
Topic: STM32 powered multimeter
Replies: 3
Views: 126

Re: STM32 powered multimeter

I think the simplest way to get +/- 32000 counts is with ADS1100 - 6pin complete acquisition system. Works great (mind it has got a fixed i2c address so in case you need several on a single i2c bus you must order chips with different addresses). I've tried as a high-side current meter with success. ...

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