Hello, I am trying to make a ANC system, where I take signal from the input microphone
through line in and the signal from error microphone through mic (for exmple).
My problem becomes when I see 2 signal are equal. This is impossibility because two signal are
completely different.
I am programming in C, with the Code Composer Studio.
I think the failure is in ADC's frequency.
I hope somebody can help me.
Excuse me, but my english is not well.

We would be more helpful if you can define your problem more precisely. It's not the
problem of English.

You see "2 signal are equal". How did you see it, from scope or from memory of DSP?

You think "failure is in ADC's frequency". Do you mean sampling frequency?

Microphone in and line in of the Codec are MUXed. That means they are actually the same line
althrough they have different input sockets. You can try to use left channel for signal and
right channel for reference. 

Wei

Hello, I am trying to make a ANC system, where I take signal from the input microphone through
line in and the signal from error microphone through mic (for exmple).
>My problem becomes when I see 2 signal are equal. This is impossibility because two signal
are completely different.
>I am programming in C, with the Code Composer Studio.
>I think the failure is in ADC's frequency.
>I hope somebody can help me.
>Excuse me, but my english is not well.

Hi. I have two senoidal signal (1 kHz and 50 kHz). One inputs to line in and other to mic. I
try programming a Active Noise Control. I have to sample two inputs alternatively. I do it with
AIC23 instructions (C language). First, open codec; later I sample mic (for example); next I
change the ADC input to the "line input", and I sample line in. I do all this at the
same time I output one of this signals (DSK5510_AIC23_write16(hCodec, &Sample)). Only one,
the same all times. But I hear two signals at the same time. The first stronger and the signal,
that I want not output, weaker.
In other programs that I make I see (from memory of DSP) two equal signal.
I think the problem become from ADC; frecuency sample, instruction time, internal capacity
ADC,...

Thank you another time.

--------------------------------------------------------------------------
We would be more helpful if you can define your problem more precisely. It's not the problem of
English.
>
>You see "2 signal are equal". How did you see it, from scope or from memory of
DSP?
>
>You think "failure is in ADC's frequency". Do you mean sampling frequency?
>
>Microphone in and line in of the Codec are MUXed. That means they are actually the same
line althrough they have different input sockets. You can try to use left channel for signal
and right channel for reference. 
>
>Wei
>
>Hello, I am trying to make a ANC system, where I take signal from the input microphone
through line in and the signal from error microphone through mic (for exmple).
>> My problem becomes when I see 2 signal are equal. This is impossibility because two
signal are completely different.
>> I am programming in C, with the Code Composer Studio.
>> I think the failure is in ADC's frequency.
>> I hope somebody can help me.
>> Excuse me, but my english is not well.

DVD-

> Hi. I have two senoidal signal (1 kHz and 50 kHz). One inputs to line in and
> other to mic. I try programming a Active Noise Control. I have to sample two
> inputs alternatively. I do it with AIC23 instructions (C language). First,
> open codec; later I sample mic (for example); next I change the ADC input to
> the "line input", and I sample line in. I do all this at the same time I
> output one of this signals (DSK5510_AIC23_write16(hCodec, &Sample)). Only
> one, the same all times. But I hear two signals at the same time. The first
> stronger and the signal, that I want not output, weaker.
> In other programs that I make I see (from memory of DSP) two equal signal.
> I think the problem become from ADC; frecuency sample, instruction time,
> internal capacity ADC,...

Your "mux" method is not a sound engineering approach.  The main problem is the DSK
5510 design does not support codec input source muxing on dynamic real-time basis. 
You will have some "memory" in the anti-alias FIR filters inside the AIC23B codec
that contain previous channel data instead of the current channel.  This will confuse
the codec filter output, possibly causing the "shadow" effect you seem to be
describing.  Even if it did work, another problem is it takes too much CPU time to be
switching (writing registers) for *every* sample -- for instance, you would not be
able to use DMA to move data between McBSP and memory buffers for increased
efficiency.

My suggestion would be to set the AIC23B for stereo line-level in and leave it.  Then
connect the mic to one of the line-level inputs, using appropriate type of mic with
built-in gain, or an external gain circuit.  Possibly you could even modify the DSK
card to add gain to one of the line-level channel circuits  since you have the
schematics.

Using this approach you will have reliable sampling -- linear, time-invariant system,
remember that from class :-)

-Jeff

> --------------------------------------------------------------------------
> We would be more helpful if you can define your problem more precisely. It's not the
problem of English.
> >
> >You see "2 signal are equal". How did you see it, from scope or from memory
of DSP?
> >
> >You think "failure is in ADC's frequency". Do you mean sampling frequency?
> >
> >Microphone in and line in of the Codec are MUXed. That means they are actually the
same line althrough they have different input sockets. You can try to use left channel for
signal and right channel for reference.
> >
> >Wei
> >
> >Hello, I am trying to make a ANC system, where I take signal from the input microphone
through line in and the signal from error microphone through mic (for exmple).
> >> My problem becomes when I see 2 signal are equal. This is impossibility because
two signal are completely different.
> >> I am programming in C, with the Code Composer Studio.
> >> I think the failure is in ADC's frequency.
> >> I hope somebody can help me.
> >> Excuse me, but my english is not well.

Your sampling methodology is new to me. As my understanding, you sample the
signal and reference alternatively from the same channel by configuring
AIC23 repeatly. Several problems arise from this setup:
1) When you try to configure AIC23 by writing to its register, AIC23 might
response after a longer delay than you expect.
2) Your signal and reference are not synchronized. It will degrade the
performance of ANC.

Why don't you just use one channel for signal and another for reference, for
AIC23 is a stereo Codec.
On 1/19/07, d...@yahoo.es <d...@yahoo.es> wrote:
> Hi. I have two senoidal signal (1 kHz and 50 kHz). One inputs to line in
> and other to mic. I try programming a Active Noise Control. I have to sample
> two inputs alternatively. I do it with AIC23 instructions (C language).
> First, open codec; later I sample mic (for example); next I change the ADC
> input to the "line input", and I sample line in. I do all this at the same
> time I output one of this signals (DSK5510_AIC23_write16(hCodec, &Sample)).
> Only one, the same all times. But I hear two signals at the same time. The
> first stronger and the signal, that I want not output, weaker.
> In other programs that I make I see (from memory of DSP) two equal signal.
> I think the problem become from ADC; frecuency sample, instruction time,
> internal capacity ADC,...
>
> Thank you another time.
>
> ----------------------------------------------------------
> We would be more helpful if you can define your problem more precisely.
> It's not the problem of English.
> >
> >You see "2 signal are equal". How did you see it, from scope or from
> memory of DSP?
> >
> >You think "failure is in ADC's frequency". Do you mean sampling
> frequency?
> >
> >Microphone in and line in of the Codec are MUXed. That means they are
> actually the same line althrough they have different input sockets. You can
> try to use left channel for signal and right channel for reference.
> >
> >Wei
> >
> >Hello, I am trying to make a ANC system, where I take signal from the
> input microphone through line in and the signal from error microphone
> through mic (for exmple).
> >> My problem becomes when I see 2 signal are equal. This is impossibility
> because two signal are completely different.
> >> I am programming in C, with the Code Composer Studio.
> >> I think the failure is in ADC's frequency.
> >> I hope somebody can help me.
> >> Excuse me, but my english is not well.
> >
> >