AFE4400: afe4400

user4992032

Part Number: AFE4400
Other Parts Discussed in Thread: AFE4403, AFE4403EVM

why i can not to get the red led signal (sfh7050:Upper part of the wrist)? i was trying every single configuration and i can not, however IR signal it is in good quality. even green signal.

over 7 years ago

0 Praveen Aroul over 7 years ago

TI__Mastermind 49766 points

Hello,

We have recd. your inquiry and will get back to you before the end of next week.

0 Prabin Yadav over 7 years ago in reply to Praveen Aroul

TI__Genius 12575 points

Hi,

Few things to try.
1) Check on finger tip with RED LED.
2) Try on some other person
3) Increase the LED current, but look for saturation.
4) Look for LED-AMB phase
5) Can you filter the data offline? Like pass it through the LPF of 20Hz

Regards,
Prabin

0 user4992032 over 7 years ago in reply to Prabin Yadav

Prodigy 100 points

I did it, now the problem is that Afe4400 is not workin whole proyect was working and turn off it then output signal is not correct it is givinme noice. regards

0 Prabin Yadav over 7 years ago in reply to user4992032

TI__Genius 12575 points

Hi,

Are you saying with the same configuration the AFE4400 is not working?
Is that the EVM's default configuration, if not try with the default configuration.

Regards,
Prabin

0 user4992032 over 7 years ago in reply to Prabin Yadav

Prodigy 100 points

Hi i am here again.

i have used discrete component in afe4403 i put it in this socket.

Resultado de imagen para bga0010

i am using the same sensor but i cant get the red signal.

i dont know how to get a red clean signal in wrist.

picture Blue signals were obtained from afe4403 in the socket. the pictures in red were obtained from your software and afe4403EVM <-- this last were in wrist so i dont understand.

if we compare your afe4403evm signals and the afe4403 in the socket that i have implemented you can see a noisy signal i mean the signal are not as clean as yours so i dont know what the problem is, What i see is i high level noise in what i have implemented compare with yours.

what can you recomend me?

0 user4992032 over 7 years ago in reply to user4992032

Prodigy 100 points

i mean this socket Resultado de imagen para bga0010

0 Prabin Yadav over 7 years ago in reply to user4992032

TI__Genius 12575 points

Hi,

looking at the waveform form your board, I can see that t your board is picking lot of noise. One reason for this could be the layout difference between your board and TI's EVM. Also looking at the image of your socket i don't see any components , are you fly wiring other components to this board? If yes, this could be one reason for the noise pickup.

Few things to try to confirm it is noise that is causing the signal degradation.
1) See the frequency spectrum of the raw data. If there are tones that means there is some signal coupling as noise.
2) Filter the raw data using LPF. You can also try doing moving averaging on the raw samples.

Regards,
Prabin

0 user4992032 over 7 years ago in reply to Prabin Yadav

Prodigy 100 points

I have implemented a passband filter for the signals and i have not problem with green and ir because as you can see the noise is too big if we compare ir with the signal about spectrum analisys i will do it, and you are right maybe is a design problem if we are talking about the socket and i am using discrete components.

0 user4992032 over 7 years ago in reply to user4992032

Prodigy 100 points

Red signal i cant filter i dont know why.

0 user4992032 over 7 years ago in reply to Prabin Yadav

Prodigy 100 points

I am Using a MCU for comunication with afe4403

0 user4992032 over 7 years ago in reply to Prabin Yadav

Prodigy 100 points

Some advice?

0 Prabin Yadav over 7 years ago in reply to user4992032

TI__Genius 12575 points

Hi,

Frequency spectrum clearly shows that the data for the RED signal is noisy as compared to other signal. Any reason when you are not able to filter the RED signal?
Can you try on some other skin tone? The reason for this is, different skin tones absorbs light differently as mentioned here,

valencell.com/.../

Regards,
Prabin

0 user4992032 over 7 years ago in reply to Prabin Yadav

Prodigy 100 points

the problem is not that i can not to filter this signal the problem is that in the signal is mounted multiples of 40 hertz signals and i dont understand the reason.

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AFE4400: afe4400