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.
The
preemphasis 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 [20].
The measures involved in the features extraction are
preemphasis, frame blocking, windowing, filter bank analysis, logarithmic compression, and discrete cosine transformation [6].
Preemphasis of speech signal is performed first using 1-st order FIR filter [7].
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.
