<p> A simple and relatively inexpensive equalizer has been developed in conjuction with a FSK modulator and demodulator (modem) for the transmission of digital data over time dispersive channels. </p> <p> The transmitter structure consists of a digital modulator followed by two filters, the first of which is a binary transversal filter (BTF), the second a conventional two-stage R-C low-pass filter. </p> <p> In the receiver structure a phaselock loop (PLL) is employed as a discriminator. Synchronization is achieved with a digital phaselock loop (DPLL). Considerable attention is placed on the error rate optimization of the receiving structure. </p> <p> The equalizer uses binary transversal filter comprising a tapped delay line, realized by a long string of metal-oxide semiconductor (MOS) flipflops, with a variable gain circuit associated with each tap in the delay line. The operation of the equalizer is adaptive in that the tap gains are adjusted rom the received data, consequently the tap gains are continually optimized. The algorithm employed for setting the tap gains is simple and can be quite easily implemented using a combination of analog and digital techniques. </p> <p> Experimental results are presented which illustrate the important features of the system implemented under a variety of operating conditions. </p> / Thesis / Master of Engineering (MEngr)

This report tested the possibility of using induction as a mean for transferring data and power so that it can be implemented as a communication medium between a terminal and measuring head mounted in a measuring frame. This would eliminate the need for the cable bunches that are used today. For testing, signal generators were used to generate FSK-signals and were transferred with the help of inductors to the oscilloscope for signal detection, this to see how the coils used in the tests behaved. Simulations of a PLL were performed to see how good it could handle FSK-demodulation. With the help of a PLL IC and the simulations a working FSK-demodulator could be assembled. This showed that the simulations and reality is in good agreement. The final results shows that it’s possible to transfer FSK-modulated data in either direction but that the desired effect isn’t possible to transfer because of the existing coupling factor that exist in the coils core used in the test. / I denna rapport testas möjligheterna att använda elektromagnetisk induktion för att överföra data och elektrisk effekt för kommunikation media mellan terminal och mäthuvudet i en mätram som används vid framställning av papper. Detta skulle kunna eliminera behovet av de besvärliga kabelbuntar som används idag. I testerna används signalgeneratorer för att generera en FSK-modulerad signal som representerar den data som överförs via spolar. Efter detektering studeras signalen på ett oscilloskop för att se hur de spolar som användes i testerna beter sig. Även simuleringar av en PLL utfördes för att se hur bra den kunde hantera FSK-demodulering. Med hjälp av kunskaper från simuleringar och en PLL IC-krets kunde en fungerande FSK-demodulator byggas ihop. Det visade att simuleringarna och verkligheten stämmer bra överens. De slutgiltiga resultaten visar att det är möjligt att skicka FSK-modulerad data i båda riktningar utan komplikationer. Den önskade effektöverföringen visar sig dock inte vara möjlig på grund av den mycket låga kopplingsfaktorn mellan spolarna som användes i testet.

Master of Science / Department of Electrical and Computer Engineering / Dwight D. Day / Low-power systems implemented on Field Programmable Gate Arrays (FPGA) have become more practical with advancements leading to decreases in FPGA power consumption, physical size, and cost. In systems that may need to operate for an extended time independent of a central power source, low-power FPGA’s are now a reasonable option. Combined with research into energy harvesting solutions, a FPGA-based system could operate independently indefinitely and be cost effective. Four simple demodulator designs were implemented on a FPGA to test and compare the performance and power consumption of each. The demodulators were a Counter that tracked the length of the input signal period, a One-Shot that counted the input edges over time, a Phase-Frequency Detector (PFD), and a PFD with preprocessing on the input signal to mitigate distortion introduces by the 1-bit subsampling. The designs demodulated a binary frequency shift keying (BFSK) signal using 10.69MHz and 10.71MHz as the input frequencies and a 1kHz data rate. The signal was 1-bit subsampled at 75kHz to provide the demodulators with a signal containing 15kHz and 35kHz. The design size, power consumption, and error performance of each demodulator were compared. At the frequencies and data rate used, the Counter and One-Shot are the most energy efficient by a significant margin over the PFDs. The error performance was nearly equal for all four. As the BFSK baseband frequencies and especially the data rate are increased, the PFD options are expected to be the better options as the Counter and One-Shot may not react quickly enough.

In the 2010, targets of National Science and Technology Program - Energy¡¥s project plan had mentioned about the development of power line communication (PLC). This shows the importance of PLC. The data transmission occur burst errors easily by the noise interference from the environment. In order to reduce the error rate, we design a modulation/demodulation chip with error correctable and high error detected ability for power line communication in this thesis. The proposed design consists of Cyclic Redundancy Check (CRC), Pulse Width Modulation (PWM), Frequency Shift Keying (FSK), Forward Error Correction (i.e. binary BCH code), and interleaving techniques. The CRC can detect the errors occurred in the digital communication. The probability of finding error is 99.997%. The BCH code is capable of correcting any combination of 3 or fewer errors in block. The function of PWM is to generate the digital pulses that exhibit the changeable pulse width according to the swing of the input voltage. In the telecommunication, FSK is a frequency modulation scheme such that the digital information can be transmitted through the discrete frequency changes of the carrier. Interleaving can make burst errors look like random errors. The design is implemented TSMC 0.18£gm process. The fabricated chip area is 1.16 millimeter square with 3.3V/1.8V supply voltages. The measured data shows that the proposed design is fully functional and consumes 55.5 £gW.

Överlagrad kommunikation är förmågan att kommunicera genom en elektrisk ledare vilken samtidigt fyller en annan funktion. För att upprätthålla kommunikationen krävs att en slags signalmodulering införs som kan slå samman information i ena änden av ledaren och urskilja samma information i den andra änden. I följande rapport kommer överlagrad kommunikation studeras för en matningsledare bestående av en DC-spänning, matningen spänningsätter en pulsgivare genom en kabel innehållande flera andra ledare. Mätningar har utförts på nuvarande system, både hur en typisk pulsgivare fungerar och hur dess installationskabel kan tänkas ha betydelse för slutresultatet. I en förstudie presenteras relevanta lösningsförslag på hur kommunikationen kan upprätthållas genom matningsledaren, förslagen med störst potential tas vidare genom att simuleringar och mätningar utförs. För att hitta de relevanta lösningarna undersöks grundläggande pulsgivarinformation tillsammans med en studie på den nuvarande marknaden. Till sist presenteras fördelar och nackdelar mellan tre olika kommunikationsexempel och tillsammans jämförs de med lösningen att dra en extra kabel vid installationen, framförallt är det prisskillnaden och platsen kretsarna tar som är av intresse. Eftersom beräkningskraftiga FPGA-kretsar var en tillgång som kunde utnyttjas skapades grunden till kommunikationen där, ingen programmering av dem beskrivs dock i rapporten. Slutgiltig lösning inkluderar kopplingen mellan en FPGA och installationskabeln. Resultatet är en robust och tillsynes säker FSK-kommunikation som har verifierats i simuleringar och fysiska uppkopplingar. Godtycklig data kan skapas i FPGA-kretsarna, skickas som halv-duplex och läsas i andra änden kabeln.

No description available.

International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / The telemetry and aerospace communities require communications equipment providing various modulation and demodulation formats. One format, with application in Space Ground Link Subsystems (SGLS), utilizes a Ternary (tri-tone) Frequency Shift-Keyed (FSK) signal Amplitude Modulated (AM) by a triangle waveform. Historically, SGLS equipment has operated with a fixed tri-tone frequency set (e.g., 65 kHz, 76 kHz and 95 kHz). The need for additional transmission channels and increased bandwidth efficiency creates the requirement for equipment with the flexibility to generate and receive varied and higher frequency tone sets. Combining analog and digital techniques, GDP Space Systems has developed the FDT001. It is an FSK/AM detector which recovers a bit rate clock at one of four selectable bit rates and reproduces ternary FSK modulation data over a widely tunable range of tone frequencies. The tuning range is expanded by using two methods of digital frequency discrimination. The following paper describes the design of the FDT001.

International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / Aerospace Report No. TOR-0059(6110-01)-3, section 1.3.3 outlines the design and performance requirements of SGLS (Space Ground Link Subsystem) services. GDP Space Systems has developed a single card slot FSK (Frequency Shift Keying)/AM (Amplitude Modulation) demodulator. An application of this service is the US Air Force Satellite Command and Ranging System. The SGLS signal is tri-tone-FSK, amplitude modulated by a modified triangle wave at half the data rate. First generation FSK/AM demodulators had poor noise performance because the signal tones were filtered and processed at IF frequencies (65, 76 and 95 kHz). Second generation demodulators suffer from "threshold" due to non-linear devices in the signal path before the primary noise filtering. The GDP Space Systems demodulator uses a 0-Hz- IF topology and avoids both of these shortcomings. In this approach, the signal is first noncoherently down converted to baseband by linear devices, then it is filtered and processed. This paper will discuss the GDP 0-Hz-IF FSK/AM (SGLS) demodulator.

International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / Flight Termination is a control action that takes place when missiles or targets violate estabished safety criteria. The flight termination receiver, part of a ground to air control loop, is characterised by high system integrity and dedication to recovering and decoding the command signals. The paper describes the factors that have influenced the design and build of a robust Pulse Code Modulation Flight Termination Receiver for use on UK Trial Ranges. This work has been carried out with the support of UK MoD(PE), A ARM 51, on contract number A ARM 13b/224.

<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>