text: Title: hyper parameters of vocoder 
  Body: I have a problem in understanding several Parameter in vocoder\hparams.py code:
  1- What is the voc_upsample_factors and why is it 3 values ​​and Why does the result of product the 3 values ​​must be equal to hop length 
  2- What is the meaning of voc_seq_len and why is it the result of (Hop length * 5)?
  3- what is the meaning of number of samples to generate at each checkpoint ?
  