Simultaneous audio and video transmission with restricted bandwidth
First Claim
1. A method for the simultaneous transmission of audio and video information over a channel having a limited bandwidth which method comprises obtaining an audio signal, providing one frame of a video image, converting the video image frame to a digitized form, using the digitized image to modulate a signal to provide marks and spaces to represent one'"'"'s and zero'"'"'s of the digitized image, the marks and spaces being in one range of the bandwidth, limiting the frequency range of the audio signals to a portion of the bandwidth other than that used by the modulation of the marks and spaces, combining the modulated image signals and the filtered audio signals, and transmitting the combined signals over the limited bandwidth channel.
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Abstract
Method for simultaneously sending audio and video signals over standard telephone lines or other channels having a restricted bandwidth which comprises obtaining a video image, digitizing the image, modulating a signal with the digitized image, obtaining audio signals and filtering the audio signals to a frequency range of the band outside that of the modulated video signal, combining the filtered audio signals and the video signal, and transmitting such signals through the restricted bandwidth channel, together with a method for receiving such signals and apparatus for sending and receiving such signals.
253 Citations
15 Claims
- 1. A method for the simultaneous transmission of audio and video information over a channel having a limited bandwidth which method comprises obtaining an audio signal, providing one frame of a video image, converting the video image frame to a digitized form, using the digitized image to modulate a signal to provide marks and spaces to represent one'"'"'s and zero'"'"'s of the digitized image, the marks and spaces being in one range of the bandwidth, limiting the frequency range of the audio signals to a portion of the bandwidth other than that used by the modulation of the marks and spaces, combining the modulated image signals and the filtered audio signals, and transmitting the combined signals over the limited bandwidth channel.
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9. Apparatus for the simultaneous transmission of audio and video information over a channel having a limited bandwidth which apparatus comprises means to receive an audio signal;
- means for providing one frame of a video image;
means for converting the video image to a digitized form;
means for converting the digitized form of the image to provide marks and spaces to represent one'"'"'s and zero'"'"'s of the digitized image, the marks and spaces being in one range of the bandwidth;
filter means to limit the frequency range of the audio signals to a portion of the bandwidth other than that used by the marks and spaces;
means to combine the converted digitized form and the filtered audio signal, and means to transmit the combined signals over the channel. - View Dependent Claims (10, 11, 12, 13, 14, 15)
- means for providing one frame of a video image;
Specification