Abstract: A variable gain differential amplifier using a single operational amplifier. A potentiometer is used in the negative feedback loop with one end connected to ground through a resistor which limits the maximum gain. The other end is connected to the output and the wiper is connected through a minimum gain limiting resistor to the inverting terminal. This provides an amplifier with good CMRR, relatively low input impedance, wide gain control and variability with a single operational amplifier.

Abstract: A audio mixer is disclosed in which selection of audio monitor signals is accomplished by an edit select switch and a plurality of monitor select switches on a monitor select portion of the mixer display. When the edit select switch is enabled, selection of audio monitor source signals is controlled by an editor. When the edit select switch is not enabled, audio monitor signals may be selected by the plurality of monitor select switches. Selection of audio monitor signals is achieved regardless of whether or not the mixer is under general crossfade control by an editor.

Abstract: An audio follow video mixer is disclosed which has a display that provides a plurality of monitor indicator LEDs corresponding to a selected audio channel. These LEDs visually indicate which channels are currently being monitored, including playback channels and line out channels. This invention permits an operator to determine which channel is being monitored during a preview operation.

Abstract: An audio mixer system using a serial editor interface is disclosed. Use of a microprocessor control circuit is disclosed to control various functions a plurality of multiple channel VTRs under the control of a mixer. Serial control signals are supplied from a video editor to a serial interface which includes a microprocessor. These control signals are decoded, and the appropriate controls of the VTRs are implemented. These controls include crossfading as well as PREVIEW/REVIEW monitoring.

Abstract: A dual colored LED indicator is provided for each channel of an audio mixing console to enable an operator to determine the status of at least a first and second device. Preferably, a red indication from the LED indicates a device is active and a green indication from the LED indicates that a device is set to become active or has just become inactive. The invention enables an operator to determine which device is set to next become active in a cross fade operation.

Abstract: The present invention is directed to an audio mixing console having main and secondary faders to independently adjust the maximum and minimum levels of a FADE OUT or FADE IN signal received from an editor associated with the mixer console.

Abstract: An audio mixer system for use with a parallel editor interface is disclosed. Use of a configuration selector to select a desired configuration of a plurality of multichannel devices is disclosed in order to enable such various configurations and reconfigurations. In one embodiment, the output of the configuration selector is provided to a memory to select prestored commands to be provided to appropriate channels. According to another embodiment, the configuration selection signals are decoded and supplied to multiplexers in combination with editor control signals to enable the editor control signals to be routed to appropriate channels.

Abstract: A servo distortion trim circuit for a DBX VCA is disclosed. The circuit comprises a feedback to the VCA which includes an inverting integrator. The input to the non-inverting terminal of the integrator is chosen to minimize distortion.

Abstract: An audio mixer system for use with a parallel editor interface is disclosed. Use of a configuration selector to select a desired configuration of a plurality of multichannel devices is disclosed in order to enable such various configurations and reconfigurations. In one embodiment, the output of the configuration selector is provided to a memory to select prestored commands to be provided to appropriate channels. According to another embodiment, the configuration selection signals are decoded and supplied to multiplexers in combination with editor control signals to enable the editor control signals to be routed to appropriate channels.