Graham, Peter

There is an increasing market demand for quartz crystals
which exhibit minimal activity dip or frequency anomalies
over a predefined temperature range. Characterization of
the frequency vs temperature (f-T) activity dip profiles of
these tight tolerance crystals is best carried out using a
system which has been expressly designed for such a purpose.
Frequency measurement accuracy and reliable temperature
control must be established in the system, along with its
being compatible with a computer controlled production or
engineering enviornment. This thesis will present design
and implementation details for a system with the
aformentioned objective of enabling the generation of
accurate crystal activity dip data. The system will provide
the user with up-to-date facilities for meeting the
temperature testing requirements of tight tolerance
crystals.

It has been conjectured that the addition of negative
feedback in an oscillator can reduce the noise generated at
frequencies close to the oscillation frequency f0. In this
thesis the noise of a bipolar transistor used in a Hartley
oscillator configuration is measured for different values of
unbypassed emitter resistance. It is found that the noise is
substantially reduced as the negative feedback introduced by
the emitter resistance is increased. A detailed noise
analysis is included, the results of which predict t he
observed reduction in the oscillator noise. The oscillation
frequency of the test oscillator is approximately 50 Mhz, but
the results are general and can be applied at any frequency.
Included are two listings of computer programs that were u sed
to perform the noise analysis.

Classes of operation of solid state power amplifiers are
surveyed with an emphasis on high efficiency radio frequency
applications. Classes A through H and S are covered, with
the first three classes combined in a unified analysis.
Time domain analyses of the switched-mode classes, D through
S, include the effects of stray reactances, switch
transition times, and load variations. For class E, a point
of optimum operation is derived, and component values are
determined assuming optimum operation. The multi-resonator
and transmission line forms of class F are analyzed. In the
last section, audio amplifier and modulator applications of
classes G, H, and S are discussed. The characteristics of
all the classes of power amplifiers discussed are summarized
in a table at the end of the paper.

PIN diodes and microstrip have found widespread use in modern
microwave systems. A design theory for the design of microwave
PIN diode switches and limiters is presented. Resonant
mi crostrip transmission line networks are shown to improve the
performance of packaged diodes. A systematic approach is used
to analyze the transmission line networks. Four types of
resonant diode switches are presented: an unmatched reverse
mode switch, a matched reverse mode switch, a series forward
mode switch, and a shunt forward mode switch. The utility of
this approach is illustrated by designing and testing several
PIN diode modules at both C and X-Band.

Collections of BASIC subroutines are developed to perform
non-general circuit analyses. These subroutines are used to evaluate
the manufacturability of a functionally trimmed thick film hybrid
circuit. Nodal, sensitivity, and tolerance analyses are used to
evaluate the effectiveness of the functional trim algorithm, and an
optimization procedure to alter the nominal circuit parameter values
for adequate margins.
The computer programs are not user-interactive, and the user has
to write a separate program to incorporate the various subroutines.
The pro6rams are written for use on the HP9835A desktop computer. The
component element types discussed are limited to resistors,
capacitors, and voltage controlled current sources.
Nodal analysis is performed by LU factorization techniques, and
sensitivity analysis by the adjoint network approach. Circuit
frequency response optimization is presented usiag the Fletcher Powell
minimization procedure and quadratic polynomial fitting. A Monte
Carlo tolerance analysis routine is developed.

The use of digital circuits in incre asingly diverse applications
and environments has greatly increased the probability
of electromagnetic interference in digital machines. The
source and control of noise in digital systems have become
major considerations in hardware design. This paper addresses
these problems and their solutions. The noise immunities of
various semiconductor families are compared showing design
tradeoffs. The effects of transmission line reflections on
digital wave forms are analyzed. The means for calculating
interference between conductors (crosstalk) are shown with
appropriate approximations. The effects of shielding conductors
and circuitry are explored with formulas for near field
calculations shown. Proper grounding and power supply decoupling
methods are shown to be paramount to proper system design.
The paper ends with an approximate noise analysis of a simple
computing machine.