Matlab中的频谱图功能

Question

我叫声谱图（Fz，window，noverlap，nff），我听不懂window，novelap，nff参数。如何准确设置参数，并且下面的频谱图函数和上面的频谱图没有参数？

window = ceil(y/4.5);
noverLap = ceil(window/4);
nff = ceil(y/4);
speech = spectrogram(Fz, hamming(window), noverLap, nff);