This disclosure describes a method and apparatus for a visual display system in a vehicle simulator to compensate for distortion and to maximize illumination in a projected image substantially at the same time. Where a spherical mirror is interposed between a curved rear-projection screen and a viewing position, certain distortions are developed which detract from realism. Such distortions are compensated for by reflecting the image off a curve folding mirror positioned so that its major axis is...

The use of a nonlinear device such as a diode inserted in series with the load impedance of a transistor amplifier stage will reduce even and odd order distortion and thus improve the overall linearity characteristics of the amplifier.

A side pincushion correction circuit is coupled to a horizontal resonant retrace circuit which includes a retrace capacitor and a horizontal deflection winding. The correction circuit includes an inductance and a controllable switch which is turned on during each horizontal retrace interval. A compensating circuit comprising secondary winding of a flyback transformer is coupled to the inductance and reflects the inductance onto the primary winding side in series with the deflection winding when ...

A transistor amplifier consisting of a modulated radio frequency generator and a detector circuit wherein the operating portion of the input-output curve of the radio frequency generator is a complement of the operating portion of the input-output curve of the detector circuit. The curvature of the radio frequency generator is controlled by variation in the current of a radio frequency voltage through a diode, changing the loading on a tuned circuit so that the amplifier may be adjusted for low,...

A distortion sound effects circuit producing an output signal corresponding to an input signal but containing one of four selected types of distortion. A compressor which includes a voltage-controlled amplifier first compresses the audio input signal within preselected limits, and the distortion operations are performed on the compressed audio signal to advantageously render the subsequent distortion operations insensitive to gross amplitude fluctuations of the input signal. The compressor inclu...

A double-sideband amplitude modulated (DSBAM) carrier passed through band-pass circuits wich are too narrow for the modulated carrier or are misaligned, may have one or both side-bands altered in relative amplitude, or in phase relative to the carrier. These effects result in amplitude modulation distortion and produce angle modulation of the carrier, with the same waveform as the amplitude distortion. In this invention the angle modulation is detected and applied to an amplitude modulator in th...

An optical distortion device which can make a contact copy of a photographic film image with one dimension of the copy lengthened or shortened while the perpendicular dimension is unchanged is comprised of a pair of cylindrical motor driven rollers, at least one of which can be driven at a very low speed. The axes of the rollers are disposed parallel to each other and to a narrow slit through which a beam of light is directed. A copy sheet such as a photographic negative and a sheet of photosens...

A harmonic distortion attenuator in an AC power supply for reducing electrical energy consumption through the suppression of transient voltages in power supply lines or the like connected to the circuitry wherein a threshold voltage clamp, responsive to a transient, closes an electrical path between the power supply lines. A triac or current responsive device is provided in parallel with the threshold voltage clamp to shunt the current flow from the clamp when the current through the clamp rises...

Errors in test results are minimized in a test system (FIG. 1) employing digital data acquisition units (121) when measuring intermodulation distortion of a voice frequency communication facility (105) by employing a unique 3-tone test signal. To this end, the three tones have predetermined amplitude, frequency and phase relationships to obtain a test signal having a desired optimum probability density function which is substantially Gaussian. Additionally, circuit noise components are eliminate...

This invention relates to a distortion factor meter circuit adapted to measure a harmonic distortion factor of a signal, particularly. A first transmission line is provided which is adapted to shape a first signal having a harmonic component to produce a DC signal, to convert the DC signal into a square wave having a width proportional to the level of the input DC signal and a predetermined periodicity, and thereafter to produce a triangular wave signal having a level linearly increasing from a ...