A distortion measurement system for measuring distortion as low as 0.002% includes an ultra low distortion oscillator having a relatively fast response which is achieved by switching the time constant of the control loops of the oscillator during settling. The analyzer section included in the distortion system has a unique notch filter which provides low distortion. This is achieved by adding together two 90.degree. all pass phase shifters. In addition, automatic tuning is provided by two feedba...

A distortion measuring device for automatic distortion measuring is disclosed, having means in the form of tunable active band stop filters with associated control circuits for automatically tuning out the fundamental while transferring the harmonics to a measuring circuit. Further is disclosed a measuring circuit for such a device, in which the measuring of the harmonics is carried out as a measuring of the amplification in active filters provided with amplification control for obtaining consta...

A distortion analysis system and method in which the occurrence of each actual transition of bits in a character is displayed in its position with reference to a first transition of the character. A plurality of light emitting elements are formed in an array of columns and mapped rows. At the time of the first transition, a first count is made to a predetermined value and then continuously repeated with each count being associated with a different one of the columns. Each time the first count re...

Harmonic distortion generated in signal processors is reduced by pre-emphasizing the processor input signal and de-emphasizing the processor output signal.

In an oscillatory signal generator circuit, exceptionally low distortion is ensured by the use of a transistor common to multiple feedback loops that causes gain to be compressed as a logarithmic function of amplitude. Changes in output impedance or loop length are compensated for or equalized by shifting the compression threshold as a function of line voltage.

Combinational distortion correction in a cathode ray tube (CRT) head-up dlay is accomplished for both optical distortion and CRT distortion by electronically predistorting the displays that appear on the face of the CRT. The corrections are performed in one step by the implementation of a complete mathematical model describing the combinational distortion patterns. The corrections to the vertical and horizontal CRT deflection voltages are represented as combinations of a plurality of transformat...

A numerical display distortion meter for signals featuring amplitude transitions at instants characteristic of the data embodied in the signals includes first and second counters of clock pulses, reset means responsive to the transitions in the distorted signal for resetting the first counter only if its count exceeds half its capacity and for resetting said second counter only if its count is less than half its capacity, and means for determining the time difference between the counts in said f...

A fiber for use in the propagation of light pulses with the attendant elimination of distortion. The fiber is useful as a delay line storage device for computer information with an extremely high-packing density capability for the bits of information. Another application is in a broadband communication system as a transmission line and in any application the fiber may be "active" as either a laser amplifier or oscillator. Basically, the invention involves the choice of fiber core and cladding si...

A linear amplifier in an automatic gain control circuit whose gain is a function of the ratio of two bias currents is obtained by selectively coupling two pairs of semiconductor devices such that the effects of nonlinearities due to the logarithmic relationship between voltage and current across a PN junction cancel. The relationship between the two pairs of devices is such that the output signal from the second pair of devices is linearly related to the input signal driving the first pair of de...

A distortion compensation apparatus returns a part of an amplified output signal of a power amplifier amplifying a transmission signal, reads a distortion compensation signal from a distortion compensation table, multiplies the transmission signal with the distortion compensation signal thereof, and inputs the signal to the power amplifier. The distortion compensation signal corresponding to a signal calculated based on an error signal that is a difference between the transmission signal and the...