International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / A simplex or ‘passive’ continuous wave and monopulse seeker tracks specific attributes of a target’s radio frequency (RF) radar return in some coordinate frame. In particular, a return carries dynamic information in amplitude (ω) and frequency (ω) at some point in azimuth (r,θ) and elevation (r,θ) planes. A passive seeker requires an illuminator beam, I(ω,φ,θ), and may require a frequency modulation on the illuminator. To model a simplex target return, we have based the dynamics on a point source radar cross section (RCS) along a line of sight (LoS) radial. The Az and El angles are equivalent to antenna placement, the attenuation and frequency dynamics are modeled in commercial off-the-shelf (COTS) software.

No description available.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / PSK demodulators have been an integral part of the signal recovery process for decades. Unless a person has designed a demodulator, how much can a person know or understand about its operation? Instruction on how to set up a demodulator’s parameters to acquire a signal is found in a manual. An explanation of why parameters are set a certain way to handle particular input signal characteristics is often not provided in a manual. This paper is designed to be a tool to aid engineers, technicians, and operators who utilize demodulators. Its purpose is to relay the functionality of a demodulator to a user so that he or she can take advantage of its control parameters and status feedback. Knowing the reasons why a demodulator is set to certain parameters may greatly reduce confusion when a system is not working properly. On site troubleshooting may be accomplished without the need to call the manufacturer of the product. Another advantage of understanding the operation will be recognized when interfacing with the manufacturer. A person will be able to relay the information to a design engineer more easily, and will understand more of the engineer’s feedback on the potential problem. Utilizing this paper as an aid to enhance operation of a PSK demodulator will bring a user one step closer to understanding the complexity of its design.

The output characteristics of five compression hearing aids in response to a transient signal were examined to determine if, the input-output function (i.e. output levels of the hearing aid as a function of input level) for a transient signal could be made to approximate that of a continuous signal, by activating the compression circuit with a second signal (activator). Input-output functions for three input compression and two output compression hearing aids were obtained in order to determine if: 1. the automatic gain control (AGC) was activated by the second signal and the transient signal output approximates that of a continuous tone, and 2. if the second tone was evident in the output of the hearing aid and thereby potentially being an interfering factor in aided auditory brainstem response (ABR) measurement.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Vita. / Includes bibliographical references. / by Max Wolff Hauser. / M.S.

Low size, low power, and wearable bio-signal recording systems require acquisition front-ends with high common-mode rejection for interference suppression and adjustable gain to provide an optimum signal level to a cascading analog-to-digital stage. This thesis presents the realization of microcontroller operated double-differential (DD) recording setup with automatic gain control (AGC) and automatic balance control, which can adjust the magnitude of recorded bio-potential signal to a target level and reject common-mode interference for full-bandwidth recording without filtering. Microcontroller code realizes the automatic control method of gain and balance adjustment by detecting, computing, and varying parameters to set timing clock pulses, which determine the gain magnitude and balance state. The automatic balance control compensates for imbalance in electrode interface impedance. The double-differential amplifier is implemented using two integrated variable gain amplifiers (ASIC) and one adder. Measured results of the variable gain amplifiers fabricated in 0.35 £gm CMOS technology show an input spot noise of 169 nV/¡ÔHz, a NEF below 10, and a circuit active area of 0.017 mm2 with a power consumption of 1.44 £gW. Measured results of the double-differential amplifier setup confirm interference suppression of 25.7 dB, tunable gain range of 39.6 dB, and 239 nV/¡ÔHz noise assuming ¡Ó10% interface mismatch. Practical measured examples incorporating the chips confirm gain control suitable for bio-potential recording and interference suppression in a balanced DD arrangement for electrocardiogram and electromyogram recording.

Šis darbas yra apie įrenginį, kuris siaurina garsinio signalo dinaminį diapazoną. Darbe lyginami automatinio stiprinimo reguliavimo metodai, bei jų taikymai pramoniniuose garso kompresoriuose. Ieškoma būdų šiuos įrenginius patobulinti. / This article is about apparatus that intentionally reduces the dynamic range of audio signals. The goal is to compare methods of automatic gain reduction, talk their implementation in industry standard hardware compressors and look for possible circuit modifications.

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We consider the problem of designing a wide-band digital receiver for an Advanced Mobile Phone Service (AMPS) cellular system, and the associated problem of choosing an appropriate Analog-to-Digital (ADC) converter. The probability density function of the voltage across a cellular receiving antenna is shown to be dependent on various cellular parameters. These parameters include mobile transmit power, mobile distance from the base station, mobile transmit frequency, and transmitting and receiving antenna characteristics. Given a high-resolution, wideband, uniform and symmetric quantizer, optimal gain factors are computed for uniformly-, sinusoidally- and normally-distributed input signals. These gain factors maximize the quantizer's Signal-to-Quantization Noise Ratio (SQNR) in a mean-square sense. Together, these techniques can be used to implement an adaptive Automatic Gain Control for cellular communications. Results from a comprehensive AMPS base station simulation will also be discussed in detail. These results illustrate several design tradeoff's including Signal-to-Noise Ratio (SNR), Carrier-to-Noise Ratio (CNR), system loading and quantizer resolution. / Master of Science