Showing 2 results for A. Ebrahimzadeh
A. Ebrahimzadeh, S. A. Seyedin,
Volume 1, Issue 4 (October 2005)
Abstract
Automatic signal type identification (ASTI) is an important topic for both the
civilian and military domains. Most of the proposed identifiers can only recognize a few
types of digital signal and usually need high levels of SNRs. This paper presents a new high
efficient technique that includes a variety of digital signal types. In this technique, a
combination of higher order moments and higher order cumulants (up to eighth) are
proposed as the effective features. A hierarchical support vector machine based structure is
proposed as the classifier. In order to improve the performance of identifier, a genetic
algorithm is used for parameters selection of the classifier. Simulation results show that the
proposed technique is able to identify the different types of digital signal (e.g. QAM128,
ASK8, and V29) with high accuracy even at low SNRs.
P. M. Farahabadi, H. Miar-Naimi, A. Ebrahimzadeh,
Volume 5, Issue 1 (March 2009)
Abstract
New equations are proposed for frequency and amplitude of a ring oscillator.
The method is general enough to be used for all types of delay stages. Using exact largesignal
circuit analysis, closed form equations for estimating the frequency and amplitude of
a high frequency ring oscillator are derived as an example. The method takes into account
the effect of various parasitic capacitors to have better accuracy. Based on the loop gain of
the ring, the transistors may only be in saturation or experience cutoff and triode regions.
The analysis considers all of the above mentioned scenarios respectively and gives distinct
equations. The validity of the resulted equations is verified through simulations using
TSMC 0.18 µm CMOS process. Simulation results show the better accuracy of the
proposed method compared with others.
