[hpsdr] Penelope MIC input

[Helmut Oeller]

Yes Ram, pin17 of the AudioCodec TLV320 should always deliver the 3/4
AVDD BIAS voltage. What happens when you feed an audio signal into the
line-input? If I recall correctly  in the past some strange things
happened sometimes with a Penelope/Magister combo. Sorry for no further
suggestions except replacement of the TLV320.

73, Helmut, DC6NY


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>
> Thanks Helmut for the reply. Yes, I checked those jumpers many times and have the PTT uninstalled, the +v and AUD one on the RING (bottom left one on the Table 3 picture on page 6). i.e. BIAS=Yes, Microphone=Ring. The shield is on the common/ground pin of the mic.
>
> What I am really surprised is why the bias voltage is not coming at all at the mic. I read the AIC23B data sheet and it should have given 3/4 of AVDD (3.3) ~= 2.475 Volts. But across the mic, I see 0 V.
>
> Ram VU3RDD
>
> On Sat, Jan 29, 2022, at 9:13 PM, Helmut Oeller wrote:
>> ***** High Performance Software Defined Radio Discussion List *****
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>> Hi Ram,
>>
>> check correct position of Mic/Bias-jumpers on Penelope board first (see
>> page 6 of Penelope manual v.1.2).
>>
>> 73, Helmut, DC6NY
>>
>>
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