# A General Question regarding OFDM symbol

I have cross across an OFDM modulator that says that

A frequency domain sequence is passed into a 64 point IFFT. A cyclis prefix is added (0.8 $\mu$sec) and creates as a result a 4 $\mu$sec time domain sequence (OFDM symbol). I am wondering The input of IFFT is discrete the output is also discrete of length 64. Then what do the authors mean by 3.2 $\mu$sec OFDM symbol? Is it a continuous time domain signal?

Fs = BW = NFFT / Tu = 64 / 3.2usec = 20MHz