A complementary distortion circuit for reducing the level of IM products in the output of a TWT amplifier. One embodiment of the invention includes a 3 db, 90.degree. coupler to divide the input signal into two components of equal amplitude but differing phase with an IM generator positioned in the path of each component. The IM generator may comprise non-linear phase modulators or non-linear amplitude modulators. The two components are then re-combined in a second, 3 db, 90.degree. coupler. The...

A raster distortion correction circuit for correcting both pincushion distortion and trapezoidal distortion of a raster on a cathode ray tube. A parabolic-shaped signal and a sawtooth-shaped signal, both having frequencies equal to the vertical deflection frequency, are supplied to the correction circuit. The amplitude and polarity of the sawtooth-shaped signal is selectively adjusted, and the adjusted sawtooth-shaped signal is combined with the parabolic-shaped signal and supplied to a current ...

The arrangement essentially comprises a corrector whose parameters are variable and controlled by a generator which during each one of periodic test time intervals, gives a random value to each of these parameters. For each such combination of parameters, a measurement of the distortion of the so corrected signal is effected and compared with a previously stored result, which was obtained with another, also stored, combination. The combination of parameters applied to the corrector outside the t...

An apparatus for producing from a photographic transparency a contact copy that is controllably elongated or compressed in one dimension only. The transparency and a photosensitive film sheet are separately transported at different linear speeds past an elongated illuminated slit by a pair of drive rollers that are driven at different rotational rates. Segmented pressure rollers keep the transparency and film sheet in contact with their respective drive rollers during transport. A differential s...

An electrical audio power amplifier is connected to receive an input informational signal from a pre-amplifying stage functioning with a transducer or pick-up device such as a magnetic phono cartridge or tape head and connected to supply a transformerless output to drive a speaker to create audio sound waves substantially free of distortion. An input differential amplifier includes a first input supplying the input informational signal and a second input supplying the output informational signal...

There is provided a circuit which may be connected across the signal path on either the input or the output of an amplifier and which is designed to distort the signal in a manner which is complementary to the distortion contributed by the amplifier so that the resultant signal is to a large degree undistorted. The circuit utilizes a diode connected across the signal path of an amplifier with means for preventing the flow through the diode of direct current voltages appearing across the signal p...

A twisting distortion correcting circuit to remove the twisting distortion in a picture on a television receiver in such a way that beam current of the television receiver is detected, and the high frequency components and the d.c. components in the detected beam current are removed so as to obtain a voltage wave form analogous to the mean horizontal deflection current wave form, and then the voltage wave form obtained is fed to the horizontal oscillation circuit whose oscillating frequency is c...

Apparatus for measuring the distortion introduced to a rectangular wave pulse by a transmission medium. Circuitry is provided for measuring the positive peak value, negative peak value and DC average value of the distorted pulse. The negative peak value and DC average value are subtracted from the positive peak value to give an indication of the delay distortion caused by the transmission medium.

An intermodulation distortion analyzer generates two pairs of sinusoidal test tones to serve as a test signal for the channel under test. The two pairs of tones simulate two respective noise band test signals but eliminate the long time averaging required for measurements when noise bands are used. A highly linear AGC circuit employs sampling at an output-controlled duty cycle to maintain a constant reference level for the analyzer. This reference level permits automatic distortion measurements ...

Raster and particularly top and bottom pincushion distortion in a cathode ray tube system is corrected by applying a drive signal from the vertical output system of a television receiver to the vertical deflection winding of a yoke to effect activation of switching elements whereby correction signals of the proper phase and amplitude and derived from the horizontal scan system are applied to the vertical deflection winding such that a vertical deflection potential at a frequency fv is modulated ...