Signal at Serial Port

[Abuzar]

Hello,

I am receiving signal at the serial port through wireless communicator at a baud rate of 9600. I want to analyze this signal and for that i need to know that what sampling frequency i should use and what is its relation with the baud rate.

Thanks alot

[Dennis_Knutson]

There is no relationship between the two. The sample rate of the signal is set by the instrument measuring the signal and transmitting it. Don't you have any specs on it?

[Abuzar]

Its an ECG wavform being digitized and transmitted through microcontroller to the zigbee and to the zigbee to the pc. So i dont have any idea of it

[Dennis_Knutson]

You'll need to contact the person that programmed the micro or look at the source code. I'm guessing this is a student project since any commercial device would have this essential piece of information documented.

[Abuzar]

I am developing this project for my particular interest, and so there hasn't any information regarding the sampling.

Kindly guide me what should i do

Thanks alot

[ejkaiser]

Can't you just look at the incoming data and count how many samples you get, say in a minute your in an hour. That should be the sampling rate then, no?

Cheers

Edgar

[Abuzar]

thanks ejkaiser what i understand from your reply that it would be directly related to the baud rate?

Am i right?

[ejkaiser]

No, not at all. The baud rate only tells you about the transmission speed on the serial line, how many bits/s you are receiving. It doesn't tell anything about the sampling rate of the data. You have to analyze how many data packages that represent a sample you are receiving per time.

You have to know (or analyze) what format the samples have.

Cheers

Edgar

[johnsold]

Abuzar,

The sampling rate for your signal is the rate at which the digitizer in the microcontroller takes samples.  If you are trying to get a good reprodcution of the waveform, the sampling rate is probably 300 to 1000 Hz.  If you are anywhere near 1000 Hz sampling, you will not be able to transmit all the data through your 9600 baud link (~ 1 ms per byte).

Lynn