A Loss and Phase Set for Measuring Transistor Parameters and Two-Port Networks Between 5 and 250 mc*

An automated loss and phase measuring set has been developed to measure, in a point‐by‐point fashion, two‐port networks over the frequency range from 20 to 20,000 cps with a maximum accuracy of 0.01 db and 0.1 degree. Manual, semiautomatic, and automatic modes of operation are provided. During automatic operation, the interval between successive data points is determined by programmed intervals of frequency, loss, and phase. These quantities are programmed either separately or in combination. Machine selection of the measurement points is controlled by comparing the program with information fed back from the signal oscillator and the measured circuit. At each selected point, frequency is measured, loss and phase are determined by self‐balancing standards, and these data are recorded on punched tape.

An Automated 20-20,000-cps Transmission Measuring Set for Laboratory Use

Haynie¹,

Rosenfeld²

1963

An Insertion Loss, Phase and Delay Measuring Set for Characterizing Transistors and Two-Port Networks Between 0.25 and 4.2 gc

Leed¹

1966

A new insertion loss, phase and delay measurement tool has been developed for characterizing gigacycle bandwidth transistors and general two‐port networks on a small signal basis over a frequency range from 0.25 to 4‐2 gc. Maximum inaccuracies are 0.1 db, 0.6 degree (over a 40‐db loss range), and 0.5 nanosecond (over a 20‐db loss range). Above 2.0 gc, the errors may double. The particular parameters selected for measurement are closely related to the scattering coefficients of the device under test, evaluated with respect to a 50‐ohm impedance level. When measuring transistors, measurement data are corrected for the residuals of jig and bias fixtures. Transformation from the measured parameters to other sets (e.g., h, y, or z matrices) is routine. In order to minimize “instrument zero‐line” and eliminate errors from circuit drift, a rapid sampling technique sequentially compares the unknown with a high‐frequency reference. Measurement accuracy is held substantially independent of test signal frequency by heterodyning the measurement information to a fixed IF, where detection is performed by “IF substitution”, using adjustable standards of loss, phase, and delay. Substantial use of automatic control circuitry contributes to an easy and facile interface between machine and operator. This paper discusses the operation and design of the test set and its use as a tool in characterizing transistors.

Measuring Frequency Characteristics of Linear Two-Port Networks Automatically

Evans¹

1969

This paper presents a new automatic technique for complete linear characterization of transistors and general two-port devices from standard insertion and bridging measurements. This technique includes a ΰάΐϋη'α-tion sequence and mathematical transformation to provide parameters inde pendent of actual test set impedances, as well as a special hardware design which allows for convenient self-measurement of the test set impedances. Knowledge of these impedances is used to reduce the measured quantities to arbitrary device parameters referenced entirely to a set of cai^ration standards. This independence of the parameters from the measuring set impedances allows for considerable reduction in the design constraints on the test set impedances and device connecting jigs.