[sdiy] Analysis of frequency variation in analogue synths

[ASSI]

Some references related to LFSR and multiple output transformations.  My 
search has not turned up any papers directly relating to the spectrum 
of (non-maximum-length) LFSR.

Multiple-output low-power linear feedback shift register design
Katti, R.S.; Xiaoyu Ruan; Khattri, H.
Circuits and Systems I: Regular Papers, IEEE Transactions on [Circuits 
and Systems I: Fundamental Theory and Applications, IEEE Transactions 
on], Vol.53, Iss.7, July 2006
Pages: 1487- 1495
Abstract: In this paper, we present a new low-power architecture for 
linear feedback shift registers (LFSRs) that produces the output of 
several clock cycles of a serial LFSR at once while reducing the 
activity factors of the flip-flop outputs. The frequency of operation 
can thus be reduced by a factor equal to the number of outputs produced 
at a time. A reduction in the frequency of the LFSR allows for a 
reduction in the power-supply voltage. Thus, dynamic power dissipation 
is reduced by up to 93% due to decreases in power-supply voltage, 
frequency, and the activity factor. Furthermore, the hardware needed 
for our implementation is far less than previous low-power 
implementations of both single and multiple-output LFSRs. Our method is 
also good for built-in self-test (BIST) applications because for most 
degrees of N it results in all 2/sup N/-1 distinct patterns.
URL: 
http://ieeexplore.ieee.org/iel5/8919/34646/01652971.pdf?isnumber=34646∏=JNL&arnumber=1652971&arnumber=1652971&arSt=+1487&ared=+1495&arAuthor=Katti%2C+R.S.
%3B+Xiaoyu+Ruan%3B+Khattri%2C+H.

Ring generators - new devices for embedded test applications
Mrugalski, G.; Rajski, J.; Tyszer, J.
Computer-Aided Design of Integrated Circuits and Systems, IEEE 
Transactions on, Vol.23, Iss.9, Sept. 2004
Pages: 1306- 1320
Abstract: This paper presents a novel methodology of designing 
generators and compactors of test data. The essence of the proposed 
approach is to use a set of transformations, which alters the structure 
of the conventional linear feedback shift registers (LFSRs) while 
preserving the transition function of the original circuits. It is 
shown that after applying the transition function preserving 
transformations in a certain order, the resultant circuits feature a 
significantly reduced the number of levels of XOR logic, minimized 
internal fanouts, and simplified circuit layout and routing, as 
compared to previous schemes based on external feedback LFSRs, internal 
feedback LFSRs, and cellular automata, all implementing the same 
characteristic polynomial. Consequently, the proposed devices can 
operate at higher speeds than those of conventional solutions and 
become highly modular structures.
URL: 
http://ieeexplore.ieee.org/iel5/43/29363/01327671.pdf?isnumber=29363∏=JNL&arnumber=1327671&arnumber=1327671&arSt=+1306&ared=+1320&arAuthor=Mrugalski%2C+G.
%3B+Rajski%2C+J.%3B+Tyszer%2C+J.

High-Speed Parallel CRC Implementation Based on Unfolding, Pipelining, 
and Retiming
Cheng, C.; Parhi, K.K.
Circuits and Systems II: Express Briefs, IEEE Transactions on [see also 
Circuits and Systems II: Analog and Digital Signal Processing, IEEE 
Transactions on], Vol.53, Iss.10, Oct. 2006
Pages:1017-1021
Abstract: This brief presents a high-speed parallel cyclic redundancy 
check (CRC) implementation based on unfolding, pipelining, and retiming 
algorithms. CRC architectures are first pipelined to reduce the 
iteration bound by using novel look-ahead pipelining methods and then 
unfolded and retimed to design high-speed parallel circuits. A 
comparison on commonly used generator polynomials between the proposed 
design and previously proposed parallel CRC algorithms shows that the 
proposed design can increase the speed by up to 25% and control or even 
reduce hardware cost
URL: 
http://ieeexplore.ieee.org/iel5/8920/36108/01715568.pdf?isnumber=36108∏=JNL&arnumber=1715568&arnumber=1715568&arSt=1017&ared=1021&arAuthor=Cheng%2C+C.
%3B+Parhi%2C+K.K.


Achim.
-- 
+<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk]>+

Factory and User Sound Singles for Waldorf Q, microQ and rackAttack:
http://Synth.Stromeko.net/Downloads.html#WaldorfSounds