Today, medical implants such as cardiac pacemakers, neurostimulators, hearing aids anddrug delivery systems are increasinglymore important and frequently used in the health caresystem. This type of devices have historically used inductive coupling as communicationmedium. Newdemands on accessibility and increased performance in technology drives newresearch toward using radio communications. The FCCMICS radio standard are specificallydevoted for implantable devices.Basically all published research on transmitters in this area are using frequency shift keying(FSK) modulation. The purpose of this thesis is to explore the viability of using phase shiftkeying (PSK) modulation in ultra low power transmitters and suggest suitable architectures.

International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / A simple, low cost radio frequency (RF) power and spectrally efficient integrated transceiver/modem architecture employing Feher’s patented Quadrature Phase Shift Keying (FQPSK) is described. The FQPSK signals presented in this paper are obtained by using additional post low-pass filters in the FQPSK architecture. This implementation significantly improves the spectral efficiency of the worldwide commercially standardized Gaussian Minimum Shift Keying (GMSK) systems. The Bit Error Rate (BER) performance of FQPSK in additive white Gaussian noise (AWGN) channel has been investigated by means of computer simulation and hardware prototype measurements. The results of the hardware and software simulations are compared to GMSK and QPSK/OQPSK performance. These results show that the filtered FQPSK modulated signal passing through a non-linear amplifier (NLA) can achieve a spectral efficiency improvement of about 60% over NLA filtered OQPSK and an integrated spectral efficiency improvement of 50% over GMSK and a better BER performance. In particular, 100 kb/s to 34 Mb/s hardware experimental results over 2.4 GHz NLA (saturated) 1 Watt system confirmed that FQPSK hardware systems attain a BER=f(Eb/N0) performance within 1 dB to 2 dB of predicted theoretical results.

International Telemetering Conference Proceedings / October 26-29, 1987 / Town and Country Hotel, San Diego, California / The three axis stabilized Indian Remote Sensing Satellite will image the earth from a 904 Km polar - sun synchronous orbit. The payload is a set of CCD cameras which collect data in four bands visible and near infra-red region. This payload data from two cameras, each at 10.4 megabits per sec is transmitted in a balanced QPSK in X Band. The payload data before transmission is formatted by adopting Major and Minor frame synchronizing codes. The formatted two streams of data are differentially encoded to take care of 4-phase ambiguity due to QPSK transmission. This paper describes the design and development aspects related to such a Data Handling System. It also highlights the environmental qualification tests that were carried out to meet the requirement of three years operational life of the satellite.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Blind adaptive equalization with application for Non-Linearly Amplified (NLA) quadrature amplitude modulation (QAM) systems in multipath selective fading channels is presented. With an offset sampling strategy in the receiver, the proposed blind equalization using Constant Modulus Algorithm (CMA) exhibits a fast convergent speed for a family of quadrature modulated systems in NLA and multipath fading channels. Feher’s patented Quadrature Phase Shift Keying (FQPSK) and Feher’s Quadrature Amplitude Modulation (FQAM) which correspond respectively to 4-state and 16-state QAM are used due to their higher Radio Frequency (RF) power and spectral efficiency in NLA channel. It has been shown that blind adaptive equalization can significantly open the eye signals in multipath frequency selective fading channels.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Space-time coding (STC) for QPSK where the transmitted signals are received with the same delay is well known. This paper examines the case where the transmitted signals are received with a nonnegligible delay differential when the Alamouti 2x1 STC is used. Such a differential can be caused by a large spacing of the transmit antennas. In this paper, an expression for the received signal with a delay differential is derived and a decoding algorithm for that signal is developed. In addition, the performance of this new algorithm is compared to the standard Alamouti decoding algorithm for various delay differentials.

International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Shaped Offset QPSK (SOQPSK) has been shown to be nearly identical in performance to Feher-patented FQPSK, which is the Advanced Range Telemetry (ATRM) program's Tier I waveform. Multi-h CPM has been selected as the ARTM Tier II waveform, because it offers 50% better spectral efficiency than the Tier I waveform. Both the Tier I and Tier II waveforms must operate in a multipath channel in order to meet the range community's telemetry requirements. This paper presents an analytical and experimental characterization of SOQPSK and Multi-h CPM in the presence of multipath. Quantitative results are presented which demonstrate the relative robustness of the ARTM Tier I and Tier II waveforms, in channels representative of a typical range environment.

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / Spectral sidelobes of QPSK, OQPSK, IJF-OQPSK, and SQAM modulated signals after nonlinear amplification are compared. It is known that OQPSK has lower spectral sidelobes than QPSK. However, in the presence of frequency selective fading, a decision-feedback adaptive equalizer is able to equalize the QPSK signal but not the OQPSK signal. By using phase pre-distortion on the OQPSK waveform before nonlinear amplification, not only is the adaptive equalizer able to equalize this signal, its spectral sidelobes are also reduced. Simulations are presented to confirm these results.

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / Shaped BPSK (SBPSK) and Shaped Offset QPSK (SOQPSK), as defined in various MIL standards, are widely employed on SATCOM links because they offer an attractive combination of good spectral efficiency, constant envelope characteristics, and interoperability with legacy equipments. More recently, numerous terrestrial applications of OQPSK and similar waveforms (Feher-patented FQPSK) have been proposed. The present paper describes a simple non-proprietary modification of the MIL-STD SOQPSK waveform which offers spectral containment and detection efficiency comparable to or better than FQPSK-B (Revision A1), while preserving a constant envelope characteristic and backward compatibility with existing equipment.

<p>Significant advanced development in the field of communication has led many designers and healthcare professionals to look towards wireless communication for the treatment of dreadful diseases. Implant medical device offers many benefits, but design of implantable device at very low power combines with high data rate is still a challenge. However, this device does not rely on external source of power. So, it is important to conserve every joule of energy to maximize the lifetime of a device. Choice of modulation technique, frequency band and data rate can be analyzed to maximize battery life.</p><p>In this thesis work, system level design of FSK and QPSK transmitter is presented. The proposed transmitter is based on direct conversion to RF architecture, which is known for low power application. Both the transmitters are designed and compared in terms of their performance and efficiency. The simulation results show the BER and constellation plots for both FSK and QPSK transmitter.</p>

Significant advanced development in the field of communication has led many designers and healthcare professionals to look towards wireless communication for the treatment of dreadful diseases. Implant medical device offers many benefits, but design of implantable device at very low power combines with high data rate is still a challenge. However, this device does not rely on external source of power. So, it is important to conserve every joule of energy to maximize the lifetime of a device. Choice of modulation technique, frequency band and data rate can be analyzed to maximize battery life. In this thesis work, system level design of FSK and QPSK transmitter is presented. The proposed transmitter is based on direct conversion to RF architecture, which is known for low power application. Both the transmitters are designed and compared in terms of their performance and efficiency. The simulation results show the BER and constellation plots for both FSK and QPSK transmitter.