Where [s.sub.2] (n) refers to the speech signal after preemphasis
and s(n - 1)refers to the last filter output value.
It can be seen from the figure, the system first preprocesses speech, including preemphasis
, overlapping frames, windowing, and the steps of voice activity detection, then the processed data are extracted by artificial feature extraction, the system using GFCC.
Chen, "Direct-detection optical OFDM transmission system with preemphasis
technique," Journal of Lightwave Technology, vol.
is done for each and every frame with [alpha]=0.97 as shown in Fig.
Feature extraction was performed using 24 ms window size with a frame shift of 8 ms, Hamming window and preemphasis
coefficient of 0.97.
In this work, preemphasis
has not been applied, since the energy of the signals acquired with the FAS is concentrated at frequencies below 1kHz and preemphasis
would reduce the discriminative capabilities of the algorithm .
The measures involved in the features extraction are preemphasis
, frame blocking, windowing, filter bank analysis, logarithmic compression, and discrete cosine transformation .
of speech signal is performed first using 1-st order FIR filter .
Most often used is Spice, which permits buffer modeling at the transistor geometry level, and all the complex preemphasis
and equalization circuitry found in SerDes buffers.
The software parameters were set to Hamming window weighting; 0.800 preemphasis
; linear time and frequency scaling; a 20-dB gray-scaling range; and FFT analysis sizes of 300 [+ or -] 50 Hz (depending upon the sample rate of the file).
With speech, the preemphasis
and AGC in the standard speech processor (Figure 29(a)) reduce the intensity range of all the frequencies.
A discussion of frequency modulation (FM) system design follows in Chapter 3, explaining how a preemphasis
schedule is designed to assure that signal quality meets the specifications in the presence of all operating conditions.