Multiple input silent audio switch
AssigneeAmpex Corporation
InventorsJay L. Flora, David A. Haycock
Life of this patent
Estimating the term…
Abstract
A silent audio switch provides switching between multiple audio sources while eliminating the "pop" caused by switching spikes. Two internal buses are used for each visible external bus, whereby a new audio signal is first switched to an off-air bus opposite an on-air bus, any switching spike is allowed to subside, and then a fast mix is made between the two buses to derive the new audio signal as the switch output signal.
Claims21
Circuit for switching between multiple input signals to provide a corresponding output signal, comprising:
- signal mixer means for supplying the output signal;
- first means for supplying a first input signal to the signal mixer means to provide the output signal;
- second means coupled to the signal mixer means for receiving a second input signal for a preselected period of time in response to a first switching control signal;
- and
- said signal mixer means being responsive to a second switching control signal only after the preselected period of time has passed for replacing the first input signal with the second input signal.
Circuit for transient-free switching between first and second audio signals of a large plurality of audio signals, comprising:
- first switching bus means for supplying the first audio signal;
- second switching bus means for receiving the second audio signal at a first instant of time;
- and
- means for replacing the first audio signal on the first switching bus means with the second audio signal on the second switching bus means at a second instant of time which occurs a preselected time period after said first instant of time which is sufficient to allow a transient therein to subside.
Circuit for switching between multiple input signals to provide therefrom an output signal, comprising:
- on-air signal bus means including a crosspoint matrix for receiving the multiple input signals and for providing an on-air signal as the output signal;
- off-air signal bus means for receiving the multiple input signals and including a crosspoint matrix responsive to a first switching control signal to provide an off-air signal;
- and
- signal mixer means coupled to the first and second signal bus means for initially supplying the on-air signal as the output signal and responsive to second switching control signals to replace the on-air signal with the off-air signal.
Circuit for switching its output between multiple audio input signals without generating switching spikes, comprising:
- signal mixer means for supplying an audio output signal;
- an on-air signal path coupled to the multiple audio input signals for supplying one of the audio input signals to the signal mixer means to define an on-air audio output signal;
- an off-air signal path coupled to the multiple audio input signals for receiving a second of the audio input signals to define an off-air audio input signal;
- and
- switching control means coupled to the signal mixer means for replacing the on-air audio input signal with the off-air audio input signal to provide a new audio output signal.
A method for switching between multiple input signals while eliminating any transient switching spikes, comprising:
- supplying one of the input signals to define a first on-air signal;
- switching a second of the input signals to define an off-air signal state for a selected time period to allow any switching spike to subside;
- and
- mixing the first on-air signal with the off-air signal only after the selected time period has passed to provide the second input signal as a new on-air signal replacing the first on-air signal.
Dependencies are inferred from the claim text.