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  • CorBee's Avatar
    10-23-2019, 09:20 AM
    CorBee replied to a thread Bat detector in Audio Projects
    Congrats, good to see you did not give up hope ;) I am interested to see how it works, did you allready try to record some bats ? regards Cor
    531 replies | 38585 view(s)
  • CorBee's Avatar
    10-07-2019, 07:11 AM
    This is another option
    6 replies | 95 view(s)
  • CorBee's Avatar
    10-06-2019, 05:23 PM
    Yeah, in the GUI they do not show until you place the component on the drawing-board.
    6 replies | 95 view(s)
  • CorBee's Avatar
    10-06-2019, 05:08 PM
    Hi, This should work, you only need to set the mixer-values to get the signal more/less on right/left. regards Cor
    6 replies | 95 view(s)
  • CorBee's Avatar
    09-26-2019, 06:18 PM
    CorBee replied to a thread Bat detector in Audio Projects
    When you look at the schematic it is not clear.
    531 replies | 38585 view(s)
  • CorBee's Avatar
    09-26-2019, 05:46 PM
    CorBee replied to a thread Bat detector in Audio Projects
    The digital stream is MONO when using MIC_IN according to me. The docs tell that we can even switch to a LEFT_ONLY mode when using MIC_IN. This is controlled in bit 6 of the CHIP_ANA_POWER register. In the current setup...
    531 replies | 38585 view(s)
  • CorBee's Avatar
    09-26-2019, 06:20 AM
    CorBee replied to a thread Bat detector in Audio Projects
    When line-in will be used for tests be aware that there are quite some reports on the difference between the line-input L and R see: https://community.nxp.com/thread/467119 It seems line-in L has cross-over talk from...
    531 replies | 38585 view(s)
  • CorBee's Avatar
    09-26-2019, 05:24 AM
    CorBee replied to a thread Bat detector in Audio Projects
    Hi at Thanks for that info. I was simply not aware of that and after reading up on the internet I see the 1st harmonic is used as another name for the fundamental-frequency. My explanation of what was tested is...
    531 replies | 38585 view(s)
  • CorBee's Avatar
    09-25-2019, 11:31 AM
    CorBee replied to a thread Bat detector in Audio Projects
    REF_CTRL, 1st/2nd HARMONIC This is the final part of the analysis based on the files Edwin has collected for many different samplerates, gains and REF_CTRL settings. The graph below shows on the Y-axis the value in...
    531 replies | 38585 view(s)
  • CorBee's Avatar
    09-24-2019, 06:45 PM
    CorBee replied to a thread Bat detector in Audio Projects
    Hi, Its Edwin's setup and the reason for the relay is simple ... we needed to be able to record many test-sequences in a row without having to manually connect/disconnect anything. Collecting many 100s of files needs...
    531 replies | 38585 view(s)
  • CorBee's Avatar
    09-24-2019, 06:23 PM
    CorBee replied to a thread Bat detector in Audio Projects
    You can read that all in the first posting I made after we have done the tests, post #464.
    531 replies | 38585 view(s)
  • CorBee's Avatar
    09-24-2019, 06:18 PM
    CorBee replied to a thread Bat detector in Audio Projects
    We have not used the MIC and preamp in our tests ...
    531 replies | 38585 view(s)
  • CorBee's Avatar
    09-24-2019, 06:05 PM
    CorBee replied to a thread Bat detector in Audio Projects
    The current BIAS is part of the REF_CTRL setting of the SGTL. Default it is set to 2 which means 12.5% above nominal. This setting can be changed to 0% (nominal) and down to -50%. We have tested this but the effects...
    531 replies | 38585 view(s)
  • CorBee's Avatar
    09-24-2019, 06:01 PM
    CorBee replied to a thread Bat detector in Audio Projects
    Hi, I am sure Edwin will have a look at your remarks. And when you build one, it will be absolutely simple to switch to line-input and no-gain is a software setting ! Cor
    531 replies | 38585 view(s)
  • CorBee's Avatar
    09-24-2019, 04:37 PM
    CorBee replied to a thread Bat detector in Audio Projects
    Hi, I think now understand your question. The narrow peaks you see are not visible in the spectra I have seen, they might be present but can also be swamped by other noise. We have looked at disabling the HP before...
    531 replies | 38585 view(s)
  • CorBee's Avatar
    09-24-2019, 04:16 PM
    CorBee replied to a thread Bat detector in Audio Projects
    I have seen those before, but it does not answer (at least for me) what you would like to see from the samples we collected. You want to see a spectrum of the so-called "silence" ?
    531 replies | 38585 view(s)
  • CorBee's Avatar
    09-24-2019, 03:46 PM
    CorBee replied to a thread Bat detector in Audio Projects
    Hi Chip, Thanks for having a look. Going through the bullets although I dont mind getting these ;) 1) I was using contrast as a term as we simply show the difference between for instance peakvalues and the...
    531 replies | 38585 view(s)
  • CorBee's Avatar
    09-24-2019, 07:13 AM
    CorBee replied to a thread Bat detector in Audio Projects
    Noise in the silent sections After splitting the wav-files into signal and "silence" I calculated the median and the 5%,95% percentiles of the "silence" to get an idea of the bandwidth of the noise. The above...
    531 replies | 38585 view(s)
  • CorBee's Avatar
    09-24-2019, 06:05 AM
    CorBee replied to a thread Bat detector in Audio Projects
    Hi Welcome to this forum ! I am interested to hear and see your progress in building the batdetector. Several people have been building the system using either the transistor or the IC opamp and it would be nice to...
    531 replies | 38585 view(s)
  • CorBee's Avatar
    09-22-2019, 07:47 PM
    CorBee replied to a thread Bat detector in Audio Projects
    Hi Walter, I know you did those tests but the discussion at that time more or less ended rather fast. Since we had all this data - with the purpose of testing the effects of using REF_CTRL - I thought it would be...
    531 replies | 38585 view(s)
  • CorBee's Avatar
    09-22-2019, 04:38 PM
    CorBee replied to a thread Bat detector in Audio Projects
    REF_CTRL tests The REF_CTRL setting on the SGTL5000 has two parts that can be changed, the VAG (VAG is the internal voltage reference for the ADC and DAC) and BIAS which controls the bias currents for the ADC). The...
    531 replies | 38585 view(s)
  • CorBee's Avatar
    09-22-2019, 04:09 PM
    CorBee replied to a thread Bat detector in Audio Projects
    Testing the frequencyresponse We are using the SGTL5000 well above its normal specifications to record the frequencies of the incoming signals. Since it was unclear if the SGTL5000 could handle all frequencies equally...
    531 replies | 38585 view(s)
  • CorBee's Avatar
    09-22-2019, 03:34 PM
    CorBee replied to a thread Bat detector in Audio Projects
    Hi Remis, Maybe wait with this until you have been able to inspect the results of this work ... I am going to show step by step the process and the results. Doing this all in a single post would be too long ;)
    531 replies | 38585 view(s)
  • CorBee's Avatar
    09-22-2019, 03:33 PM
    CorBee replied to a thread Bat detector in Audio Projects
    Initial Processing The WAV files were directly loaded into the jupyterlab-environment using the SciPy library. After loading the data was scaled to a maximum -1..1 range by dividing with 32768. All data was then...
    531 replies | 38585 view(s)
  • CorBee's Avatar
    09-22-2019, 02:47 PM
    CorBee replied to a thread Bat detector in Audio Projects
    What happened before ? At the beginning of september I tested if changing the MIC_CTRL and REF_CTRL settings on the SGTL5000 had effects on signalstrength and spectrum. My tests were showing clear effects but it was...
    531 replies | 38585 view(s)
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