FFT algorithms for SIMD parallel processing systems

A modular fast Fourier transform processor which employs identical processor cards, each of which has a butterfly, memory units which send and receive data to and from the butterfly and a pair of input ports and a pair of output ports. The cards are interconnected through these ports to execute a fast Fourier transform decomposition in accord with Singleton's algorithm. The speed and capacity of the processor may be increased in a gradual manner by employing more of the processor cards.

FFT Parallel processor having mutually connected, multiple identical cards

Different fast Fourier transform (FFT) algorithms for hardware implementation have been considered. We propose an implementation whereby two radix-N1/2passes are carried out in parallel and in which each N1/2-point transform is carried out via a serial input parallel output transform circuit. The processing rate is one clock cycle per input point for the N-point transform regardless of the value of N chosen. The circuit is being implemented with TTL logic and will be used to perform spatial frequency domain filtering on two dimensional infrared camera images in real time; real time meaning processing between frame display.

Implementation of a fast Fourier transform (FFT) for image processing applications

Publisher Summary This chapter provides an overview of very long baseline interferometer (VLBI) systems. In VLBI, the undetected signals received at remote, unconnected radio telescopes are stored in such a way that they can be recovered at a later time and processed in a fashion similar to conventional interferometry. Several essential components are required to make two remote telescopes into an interferometer which include: a stable local-oscillator system for signal frequency conversion; a video converter for conversion of the intermediate frequency (i.f.) signal to a video band; a means of synchronizing the clocks at the stations; a device for storing the received signal and precise timing information; and a playback system. The antennas and front-end amplifiers used in other applications of radio astronomy are generally adequate for VLBI measurements. There are no special tracking requirements for the antennas. Local oscillators in single-telescope continuum studies can be free running and, in spectral-line studies, need only be frequency locked, those in VLBI applications must be phase locked to high-performance frequency standards. A general block diagram of a VLBI system is provided in the chapter along with an overview of single-sideband video converter. Details of IBM-compatible, digital-recording system are also presented.

5.3. Very Long Baseline Interferometer Systems

Physiological parameters such as Heart Rate (HR), Beat-to-Beat Interval (IBI) and Respiration Rate (RR) are vital indicators of people’s physiological state and important to monitor. However, most of the measurements methods are connection based, i.e. sensors are connected to the body which is often complicated and requires personal assistance. This paper proposed a simple, low-cost and non-contact approach for measuring multiple physiological parameters using a web camera in real time. Here, the heart rate and respiration rate are obtained through facial skin colour variation caused by body blood circulation. Three different signal processing methods such as Fast Fourier Transform (FFT), independent component analysis (ICA) and Principal component analysis (PCA) have been applied on the colour channels in video recordings and the blood volume pulse (BVP) is extracted from the facial regions. HR, IBI and RR are subsequently quantified and compared to corresponding reference measurements. High degrees of agreement are achieved between the measurements across all physiological parameters. This technology has significant potential for advancing personal health care and telemedicine.

Non-Contact Physiological Parameters Extraction Using Camera

An FFT algorithm is presented that can be implemented with serial-access memory. For clarity and insight the emphasis is upon conciseness and illustration rather than shorthand mathematical notation. The algorithm's potential for high-speed implementation is demonstrated by studying variations on the basic algorithm that include both higher radix algorithms and parallel arithmetic unit algorithms. The fact that these sophisticated variations can be seen and understood by inspection of the basic algorithm emphasizes its simplicity. The algorithm is shown very suitable for efficient special-purpose implementation by the functional independence of the transform node from the particular node in the transform or the number of nodes in the transform, i.e., one node in canonical form (for a given radix) represents the entire FFT algorithm. The algorithm is shown to perform variable length transforms at full operational efficiency with minor modification, thus emphasizing its relative versatility. The possibly unexpected conclusion is made that the FFT implementation using parallel arithmetic units is more efficient in terms of speed and probably design effort and hardware, than one using high radix algorithms.

https://ieeexplore.ieee.org/iel6/8337/26092/01162368.pdf

R. Veenkant

Papers

A serial minded FFT