Design of Plural-Multiplier Based on CORDIC Algorithm for FFT Application
CORDIC plural-multiplier is the key module to affecting the speed and accuracy of FFT processor. Considering these demands, the problem of CORDIC algorithm is discussed in detail and the according optimization methods are given in this paper. Then, the hardware pipe-lining structure of the CORDIC multiplier is put forward. Comparison results about RTL simulation results with MATLAB calculation indicate that the design is feasible and practical.
18.Hardware Efficient Architecture for Generating Sine/Cosine Waves
This paper presents a hardware efficient architecture for generating sine and cosine waves based on the CORDIC (Coordinate Rotation Digital Computer) algorithm. In its original form the CORDIC suffers from major drawbacks like scale-factor calculation, latency and optimal selection of micro-rotations. The proposed algorithm overcomes all these drawbacks. We use leading-one bit detection technique to identify the microrotations. The scale free design of the proposed algorithm is based on Taylor series expansion of the sine and cosine waves. The 16-bit iterative architecture achieves approximately 4.5% and 6.7% lower slice-delay product as compared to the other existing designs. The algorithm design and its VLSI implementation are detailed.
19.Approach lightning system/pilot controlled lightning at airport runway for energy conservation
Pilot Controlled Lighting (PCL), also known as Aircraft Radio Control of Aerodrome Lighting (ARCAL) or Pilot Activated Lighting (PAL), is a system which allows aircraft pilots to control the lighting of an airport or airfield’s approach lights, runway edge lights, and taxiways via radio. At some airfields, the aerodrome beacon may also be ARCAL controlled. ARCAL is most common Anton or little-used airfields where it is neither economical to light the runways all night, nor to provide staff to turn the runway lighting on and off. It
enables pilots to control the lighting only when required, saving electricity and reducing light pollution. The ARCAL frequency for most aerodromes is usually the same as the UNICOM/CTAF frequency, although in some rare cases, a second ARCAL frequency may be designated to control the lighting for a second runway separately (an example of this is runway 01/19 at the airport in Sydney, NS). To activate the lights, the pilot clicks the radio transmit switch on the ARCAL frequency a certain number of times within a specified number of seconds.
There are two type of ARCAL systems, type J and type K. When either type of system is activated, a 15-minute countdown starts, after which the lights turn off. While the lights are on, whenever a lighting command is issued, whether it changes the lighting intensity or not, the 15-minute countdown is reset. At some airfields, the lights may flash once to warn pilots that the lights are about to go off, before turning off two minutes later.When using ARCAL, it is strongly recommended that aircraft on final approach to the airfield issue a fresh lighting command, even if the lights are already on (especially if the lights were activated by another aircraft). This is so that the lighting does not turn off at a critical moment (such as when crossing the runway threshold).
