Hi Mohsen,

Everything that implies a sampling frequency, is a digital file. Digital files are discrete time signals. Analogue means that you have to have a continuous signal without interruption. Below you can find an explanation regarding digital and analogue recording in music.

http://en.wikipedia.org/wiki/Comparison_of_analog_and_digital_recording

In your specific case, EMG is a digital signal, if you plot it as a scatterplot you will see some "little squares" which represent your data, each one correspond to a single EMG value in time. The density of the squares in one second represent your sampling frequency, if you have 100 square per second it means that the system has a sampling frequency of 100 Hertz.

If you need some help with the file, just write me :)

Hope this informations will be useful.

Ivan

The electromyogram is intrinsically an analogue signal. If you sample it and use an A/D converter to store it, then you made it digital (as you can do with any band-limited analogue signal), but the original EMG signal is clearly an analogue signal.

hello Mohsen,

basically all EMG recordings are continuous as they come from an analogous source. When sampling the signal, you will make your variable "discrete" as explained by Ivan, but it's not because a continous variable is sampled that you will handle it in a discrete way for analysis. For example, even sampled, your signal will have continuous variable properties (amplitude, latency for one recording, or mean/median/standard deviation... for several signals).

Hope it helped ?

Emmanuel

thank you all for your best reply.

so according to your replies the EMG signals are continuous in nature but when it was became digital the obtained variables are discrete.

thanks a lot again for your contributory guidance.

yours truly.

Alighanbari

Hi Mohsen

In my opinion, despite the fact that, the EMG signals are continuous in nature, there are some commercial software which can extract discrete data points from the signals.