Abstract: A method for a machine or group of machines to watermark speech audio transmissions includes receiving a speech audio signal, receiving a watermark signal including a message of multiple bits, each bit having one of two values, each value represented by one of two symbols, each of the symbols corresponding to a respective audio segment, and at a time t1, transmitting a first transmission including at least some of the multiple bits in multiple spectral channels of the speech audio signal, each spectral channel corresponding to a different frequency range, wherein a first one of the multiple spectral channels carries a first bit from the multiple bits while at the same time a second one of the multiple spectral channels carries a second bit from the multiple bits different from the first bit.

Abstract: A method for a machine or group of machines to watermark speech audio transmissions includes receiving a speech audio signal, receiving a watermark signal including a message of multiple bits, each bit having one of two values, each value represented by one of two symbols, each of the symbols corresponding to a respective audio segment, and at a time t1, transmitting a first transmission including at least some of the multiple bits in multiple spectral channels of the speech audio signal, each spectral channel corresponding to a different frequency range, wherein a first one of the multiple spectral channels carries a first bit from the multiple bits while at the same time a second one of the multiple spectral channels carries a second bit from the multiple bits different from the first bit.

Abstract: Providing feedback regarding detectability of a watermark message produced by a watermarking encoder may include receiving a watermark detectability indication corresponding to detectability of the watermark message, and determining an enhancement indication corresponding to a prescribed enhancement to a watermark signal in which the watermark message is embedded based on the watermark detectability indication.

Abstract: A system for monitoring detectability of a watermark message produced by a watermarking encoder includes an input that receives a watermarked signal having spectral channels in which the watermark message is embedded. The system also includes channel separators each associated with a respective spectral channel of the watermarked signal and configured to separate the watermarked signal into spectral channels. The system also includes bin separators configured to separate the spectral channels into frequency bins. The system also includes a detector configured to detect a frequency bin corresponding to a symbol that appears in a plurality of the spectral channels. The system also includes a detectability estimator configured to establish a measure of the detectability of the watermark message embedded in the watermarked signal based at least in part on the frequency bin corresponding to the symbol that appears in the plurality of the spectral channels.

Abstract: A device for extracting a watermark signal from an output signal of a watermarking encoder in which the output signal includes an input signal portion corresponding to an input signal to the watermarking encoder and a watermark signal portion corresponding to the watermark signal includes an input configured to receive the input signal and the output signal. The device further includes an adjustment signal generator configured to generate a gain adjustment signal and a delay adjustment signal based on the input signal and the output signal, a gain and delay adjustor configured to adjust gain and delay of the output signal or the input signal based on the gain adjustment signal and the delay adjustment signal, respectively, to generate an adjusted output signal or an adjusted input signal, respectively, and an output configured to transmit a difference between the input signal and the adjusted output signal or a difference between the adjusted input signal and the output signal as the watermark signal.

Abstract: A device for enhancing a watermark signal extracted from an output signal of a watermarking encoder including an input signal portion corresponding to an input signal to the watermarking encoder and a watermark signal portion corresponding to the watermark signal includes an input configured to receive the input signal and the watermark signal, an enhancement module operatively connected to the input and configured to a) enhance the watermark signal at least in part by adjusting a gain of the watermark signal to obtain an enhanced watermark signal, and b) generate an enhanced output signal including an input signal portion corresponding to the input signal and an enhanced watermark signal portion corresponding to the enhanced watermark signal.

Abstract: An apparatus and method simulates more accurately the natural statistics of a physical reverberation process. A new filter design is provided having a comb shaped group delay. Gain minimums at a plurality of frequencies are combined with a delay line to create a constant reverberation time independent of frequency while allowing for temporal spreading. In addition, the connection topology between the plurality of energy transmission networks is temporally randomized to facilitate energy distribution within the reverberation apparatus. Both the temporal and spectral responses are actively changed on each iteration of the energy recirculation. By making the response have a high echo density and a lack of spectral coloration in the decay, the illusion of a natural process is enhanced.

Abstract: An apparatus and method simulates more accurately the natural statistics of a physical reverberation process. A new filter design is provided having a comb shaped group delay. Gain minimums at a plurality of frequencies are combined with a delay line to create a constant reverberation time independent of frequency while allowing for temporal spreading. In addition, the connection topology between the plurality of energy transmission networks is temporally randomized to facilitate energy distribution within the reverberation apparatus. Both the temporal and spectral responses are actively changed on each iteration of the energy recirculation. By making the response have a high echo density and a lack of spectral coloration in the decay, the illusion of a natural process is enhanced.

Abstract: An apparatus and method simulates more accurately the natural statistics of a physical reverberation process. A new filter design is provided having a comb shaped group delay. Gain minimums at a plurality of frequencies are combined with a delay line to create a constant reverberation time independent of frequency while allowing for temporal spreading. In addition, the connection topology between the plurality of energy transmission networks is temporally randomized to facilitate energy distribution within the reverberation apparatus. Both the temporal and spectral responses are actively changed on each iteration of the energy recirculation. By making the response have a high echo density and a lack of spectral coloration in the decay, the illusion of a natural process is enhanced.

Abstract: An apparatus and method simulates more accurately the natural statistics of a physical reverberation process. A new filter design is provided having a comb shaped group delay. Gain minimums at a plurality of frequencies are combined with a delay line to create a constant reverberation time independent of frequency while allowing for temporal spreading. In addition, the connection topology between the plurality of energy transmission networks is temporally randomized to facilitate energy distribution within the reverberation apparatus. Both the temporal and spectral responses are actively changed on each iteration of the energy recirculation. By making the response have a high echo density and a lack of spectral coloration in the decay, the illusion of a natural process is enhanced.

Abstract: A digitizing tablet is disclosed in which two sets of circuitous conductive lines form grids each connected at one end to a surrounding conductive loop. All outputs are measured from the conductive loop as a multiplexor sequentially grounds the grids one at a time. The outputs are fed through linear spatial filters which are used to produce intermediate signals which are in turn combined to arrive at raw position signals for a position indicating coil located over the work surface. Separate sets of linear spatial filters may be used to produce two raw position signals differently responsive to tilt which can then be combined to arrive at a true position signal insensitive to tilt.

Abstract: A digital data communications system transmits digital data over a telephone line using frequency multiplexing for the different channels. Each channel includes a receiver and a transmitter coupled to the telephone line at spaced points. Each transmitter includes an FSK modulator, a bandpass filter of controllable bandwidth centered about 5 kHz with its bandwidth controlled by a bandwidth select signal related to the bandwidth needed to transmit data over that channel. A mixer combines the output of the bandpass filter with a local oscillator signal of frequency related to the selected channel to provide a difference frequency signal that is applied to a lowpass filter having a cutoff at 3 kHz that is coupled to the telephone line. Each receiver includes a lowpass filter having a cutoff at 3 kHz that couples the line to a mixer.

Abstract: A digitizing tablet is disclosed in which two multiplexors are connected to alternate conductive loop elements in each plane of elements. The two multiplexors are connected to a differential amplifier. The signals from the differential amplifier are demodulated. The demodulated signal is provided to an integrator. A microprocessor controlled reset switch is connected across the integrator to reset the integrator after the completion of each measurement. Grounded copper strips are used in the space formed within and between the conductive loop elements of the digitizing tablet to shield the loop elements from capacitive interference.

Abstract: A position indicating implement is disclosed having a first coil connected to a current source and a second coil inductively coupled with the first coil. A capacitor is connected in series with the second coil so that the current in the first coil induces a phase shifted current in the second coil. A tip extends from the barrel of the position indicating implement of the present invention. The tip is designed for placement on and movement over a digitizing tablet. A switch has been located near the tip so that it is easily accessible to a user's finger while holding the implement.The power source providing an alternating current to the first coil includes a digital switching circuit for producing a step function which approximates a sine wave and lacks any components at the second, third, fourth, fifth and sixth harmonics. The step function is filtered to produce a sine wave for delivery to the first coil.

Abstract: An electronic reverberation apparatus, for producing artificial reverberation on a purely electronic basis with a digital computer, comprises a plurality of loops having different delay times and adapted to form sound repetitions of diminishing intensity. Some of the loops have short delay times and have an all-pass characteristic. Others of the loops have long delay times. The loops are provided with tappings each of which has a particular delay time associated with it. The delay times of the tappings themselves and the sums, differences and quotients of these delay times are in a non-harmonic relationship to one another. Each tapping feeds a corresponding damping element whereby the output from each successive tapping is reduced such that the reduction in energy corresponds to an exponential function, and a delayed and repeated combination of unreverberated input signals is fed to an output from the loop circuit. For naturalness the output of each reverberation delay unit is randomly damped.