An accurate and fast behavior modeling procedure is presented for codesign of active optical device with circuitry. The developed method is based upon defining partial elements (PEs) and their measurement-based partial element equivalent circuits (M-PEEC), associating design rules with them, and characterizing them through the use of test structures. The test structures are designed such that they can include only sensitive combinations of predefined building blocks, and they are measured over a wide band of frequencies using network analysis techniques. Measurement-based partial element equivalent circuits of the building blocks are derived from the measured s-parameters of the test structures by nonlinear optimization methods. The method has been experimentally verified using metal-semiconductor-metal photodetectors. The method has also been verified with circuits using simulations, with good results obtained.

Higher data rate hard disk drives(HDD) and improved read channel electronics are demanding preamplifier performance be extended well beyond 1 Gb/s. Historically, preamplifier power requirements were of low priority; however, with increased demand for battery powered devices such as laptops, MP3 players, personal video recorders, andmanyother wireless hand-held devices, power consumption has become an important design parameter.Furthermore, in order to continue to increase drive capacities, new read-write head technologies(vertical recording and TGMR heads) are demanding innovative preamplifier circuitsolutions.Today's production preamplifiers possess a wide band response of 2.5 MHz-600 MHz; however next generation preamplifiers willrequire response greater than 250 KHz-1 GHz.Low corner frequencies below 250 KHz present read recovery (sleep-to-read, write-to-read, etc) challenges which can limit drive capacity. This project targets a > 2 Gb/s TGMR (tunneling giantmagneto-resistive) read path for verticalrecording HDDs. A high performance BiCMOS process (IBM's 0.5?m 5HP process)is essential due to the large transconductances, low noise and highspeed requirements of the read path's first stage. System frequency limitations at the input are a result of the large TGMR read sensor and preamplifier input capacitance. Due to read head and preamplifier manufacturingvariations, resistive feedbackaroundthe firststage is usedto seta controlled input impedance targeted to match the interconnect transmission line. Head resistance variations lead to gain variations; however, the TGMR element becomes more sensitive with larger resistance. This, to a first order approximation, acts like an automatic gain control and reduces variations in gain due to the head.

Three different topics associated with their respective applications are proposed in this thesis. The first topic is the implementation of a transimpedence preamplifier for 16 Mbps infrared transceiver modules. The design of the preamplifier is aimed at the VFIR (very fast infrared) which is supposed to provide a 16 Mbps data transmission rate. The second topic is focused on the implementation of a robust reference clock generator design for DDR synchronous devices. A pulse generator circuit to generate pulses corresponding to the rise edges and fall edges of a given clock is presented. The third topic is to carry out a cost-effective voice dialer. It focuses on the voice feature extraction and the recognition of Chinese numbers 0 to 9. We present a low-cost method to implement such an algorithm by using 8051-ICE.

Higher data rate hard disk drives(HDD) and improved read channel electronics are demanding preamplifier performance be extended well beyond 1 Gb/s. Historically, preamplifier power requirements were of low priority; however, with increased demand for battery powered devices such as laptops, MP3 players, personal video recorders, andmanyother wireless hand-held devices, power consumption has become an important design parameter.Furthermore, in order to continue to increase drive capacities, new read-write head technologies(vertical recording and TGMR heads) are demanding innovative preamplifier circuitsolutions.Today's production preamplifiers possess a wide band response of 2.5 MHz-600 MHz; however next generation preamplifiers willrequire response greater than 250 KHz-1 GHz.Low corner frequencies below 250 KHz present read recovery (sleep-to-read, write-to-read, etc) challenges which can limit drive capacity. This project targets a > 2 Gb/s TGMR (tunneling giantmagneto-resistive) read path for verticalrecording HDDs. A high performance BiCMOS process (IBM's 0.5?m 5HP process)is essential due to the large transconductances, low noise and highspeed requirements of the read path's first stage. System frequency limitations at the input are a result of the large TGMR read sensor and preamplifier input capacitance. Due to read head and preamplifier manufacturingvariations, resistive feedbackaroundthe firststage is usedto seta controlled input impedance targeted to match the interconnect transmission line. Head resistance variations lead to gain variations; however, the TGMR element becomes more sensitive with larger resistance. This, to a first order approximation, acts like an automatic gain control and reduces variations in gain due to the head.

This thesis deal with the audio preamplifier with input selector. It describes all designed parts of this device. It selects and describes all suitable components. Describes the whole process of electronics design in this device. Then describes the design, manufacture, assembling and testing of the PCB. In conclusion it shows the achieved results and electrical parameters of the device.

No description available.

Much of the current research in magnetic resonance engineering focuses on reducing the acquisition time for obtaining an image while simultaneously maximizing the Signal to Noise ratio (SNR) of the image. It is known that improvement in imaging time or resolution is obtained at the cost of SNR. Therefore wherever possible, RF coil engineers design the coil in such a manner so as to maximize SNR for that coil design. In one such design consideration, most coil designers prefer placing low impedance preamplifiers near the coil. The further the pre-amplifiers are from the coil, the greater will be the signal loss due to transmission and higher will be its input impedance as perceived at the coil which would degrade inter-coil isolation. Owing to the current trend of using increasing number of receiver channels (32, 64 or 128) for parallel imaging, placing the preamplifiers near the coil would greatly complicate the coil construction. The primary objective of this research was to find the relation between SNR and referred preamp impedance and whether preamps need to be placed on the coil, or if they can be placed outside the magnet at the end of a transmission line which would simplify the construction of large count array. In addition, SNR was studied as a function of coil design parameters - coil loading, array coil separation, and system frequency. Both theoretical and experimental methods were used to undertake this investigation. A popular electromagnetic modeling technique, finite difference time domain (FDTD), was used to model SNR in arrays of two 3 inch loop coils at 3T and 1.5T. Results were also verified through bench measurement at 3T and 1.5T and by evaluating SNR. To verify the robustness of our results and to assess the possibility of using low cost standard 50 ohm preamps, we carried out additional bench measurements at 4.7T. Results demonstrated that preamplifier placement is critical at low field strength. At higher field strength, SNR degradation due to preamplifier placement was less owing to heavier coil loading.

Abstract This thesis describes the development of integrated structures and circuit implementations for the receiver channel of portable pulsed time-of-flight laser rangefinders for industrial measurement applications where the measurement range is from ∼1 m to ∼100 m to noncooperative targets and the required measurement accuracy is from a few millimetres to a few centimetres. The receiver channel is used to convert the current pulse from a photodetector to a voltage pulse, amplify it, discriminate the timing point and produce an accurately timed logic-level pulse for a time-to-digital converter. Since the length of the laser pulse, typically 5 ns, is large compared to the required accuracy, a specific point in the pulses has to be discriminated. The amplitude of the input pulses varies widely as a function of measurement range and the reflectivity of the target, typically from 1 to 100 ... 1000, so that the gain of the amplifier channel needs to be controlled and the discrimination scheme should be insensitive to the amplitude variation of the input signal. Furthermore, the amplifier channel should have low noise in order to minimize timing jitter. Alternative circuit structures are discussed, the treatment concentrating on the preamplifier, gain control circuitry and timing discriminator, which are the key circuit blocks from the performance point of view. New circuit techniques and structures, such as a fully differential transimpedance preamplifier and a current mode gain control scheme, have been developed. Several circuit implementations for different applications are presented together with experimental results, one of them being a differential BiCMOS receiver channel with a bandwidth of 170 MHz, input referred noise of 6 pA/√Hz and maximum transimpedance of 260 kW. It has an accuracy of about +/- 7 mm (average of 10000 measurements), taking into account walk error with an input signal range of 1:624 and jitter (3s). The achievable performance level using integrated circuit technology is comparable or superior to that of the previously developed commercially available discrete component implementations, and the significantly reduced size and power consumption open up new application areas.

The diploma thesis deals with the design of hybrid microphone preamplifier with stepless choice of amplification technology between active part using tube or semiconductor elements. Before the design, the basic physical relations of electroacoustics were described. Problems of connection of audio devices, their voltage and noise conditions. At last technical properties of microphones and tubes were described. In the practical part, the overall structure of the hybrid preamplifier is designed and the goals of the thesis are set. This is followed by a detailed design of the preamplifiers. From input circuits through individual amplifier stages of the semiconductor and tube sections to the output of the device. Much of the circuit was tested by software simulations. Based on the results obtained in the design of the signal part of the preamplifier, the power circuits were designed. Finaly the preamplifier functionality was verified by measurement on the Audio Analyzer.

The main content of this masters’s thesis is designing of an audio mixing desk and simulation of individual components in software OrCAD. The most important parts of the device are input preamplifiers for dynamic, electret and condenser microphones, stereo unbalanced inputs and balanced line level preamplifiers, equalization circuits and LED level indicators of individual channels, headphone listening circuit, 10-band equalizer, audio spectrum analyzer, circuits with balanced signal for main outputs and power supply circuits.