Abstract: Data transmission apparatus for multiplexing one or more channel data streams of equal, predetermined, data rate into a transmission data stream comprises: means for generating a control data stream of the same data rate as the channel data rate, in which first periodically repeating portions of the control data stream provide a synchronisation signal and second periodically repeating portions of the control data stream provide identification data specifying information about the channel data streams with reference to a predetermined ordering of the channel data streams; and means for multiplexing the control data stream with the one or more channel data streams in a cyclic pattern of equally-sized data portions so that a data portion from the control data stream is followed by data portions from each of the channel data streams according to the predetermined ordering of channel data streams.

Abstract: Audio processing apparatus comprises one or more touch-sensitive controls for adjusting a gain applied to an audio processing channel in response to movement of a user's hand while touching the controls; a detector for detecting a predetermined sequence of activation of a touch sensitive control by the user; and a signal switch responsive to a detection of the predetermined sequence of activations to toggle between a first mode of operation in which the audio processing channel is operable to suppress an input audio signal and a second mode of operation in which the input audio signal is not suppressed.

Abstract: A signal processor for 1-bit signals comprises a fifth order Delta-Sigma Modulator (DSM) having an input for receiving a 1-bit signal and an output at which a processed 1-bit signal is produced by a quantizer. The quantizer receives a p-bit signal from a series of five signal integration stages. Each stage comprises a first 1-bit multiplier coupled to the input, a second 1-bit multiplier coupled to the output, an adder which sums the outputs of the coefficient multipliers and an integrator which integrates the output of the adder. A final stage comprises a coefficient multiplier and an adder. The adder sums the output of the coefficient multiplier and the output of the integrator of the preceding integration stage. The coefficients are chosen to provide an overall attenuation of the input signal and of the quantization noise produced by the quantizer. Reduction of quantization noise allows several DSMs to be connected in series by preventing the build-up of excess noise, which may compromise stability.

Abstract: A differential microphone (50) produces a differential pair of output signals which are applied by a differential analogue amplifier (52). The amplified differential signals are converted to 1-bit form by a pair of analogue to digital converters (54, 55) and are combined in a 1-bit Delta Sigma Modulator.

Abstract: An array of user-operable controls and a proximity sensing apparatus are contained in an apparatus wherein the proximity sensing apparatus detects whether a user's hand is within a predetermined distance from the controls. Once the user's hand is a predetermined distance from the controls, a display screen displays screen icons associated with its respective control. The screen icons are controlled by a display processor which responsive to the user's hand being within a predetermined distance from the controls, alters the screen icon associated with its respective control.

Abstract: A digital audio signal processor processes digital audio signals having a first sampling rate S1. The processor has a multiplicity of manually adjustable controls (403) for setting desired parameters of signals to be processed. Sampling means (404) sample each control (403) setting at a second sampling rate S2 less than the first rate S1 to determine the settings thereof. Applying means (401) responsive to the sampling means apply the sampled settings to the signals. For each control the applying means determines the difference of successive samples of setting and applies to the signal, subject to control by that control, increments of setting each increment being a predetermined fraction 1/n of the said difference at a rate nS2 which is n times the said second sampling rate S2.

Abstract: A microphone comprises a housing; an acoustic-to-electrical signal transducer disposed within the housing, the transducer being operable to generate an analogue audio signal; and a one-bit analogue-to-digital converter disposed within the housing for converting the analogue audio signal into a one-bit digital audio signal for transmission to other, external, audio processing apparatus.

Abstract: Signal processing apparatus is described in which at least two sets of automated signal processing functions are controlled by stored automation commands, at times dependent upon at least two respective timecode signals which may each be associated with a respective source signal supplied to the signal processing apparatus.

Abstract: A signal processing system in which a differentially quantized digital signal is used, the digital signal having two bits which represent only three values, of which one value (10 or 01) is zero and the other two (11 and 00) values represent a positive value and a negative value respectively.

Abstract: A signal processor for 1-bit signals comprises a fifth order Delta-Sigma Modulator (DSM) having an input 4 for receiving a 1-bit signal and an output 5 at which a processed 1-bit signal is produced by a quantizer Q. The quantizer Q receives a p-bit signal from a series of 5 signal integration stages. Each stage comprises a first 1-bit multiplier An coupled to the input 4, a second 1-bit multiplier Cn coupled to the output 5, an adder 6n which sums the outputs of the coefficient multipliers and an integrator 7n which integrates the output of the adder 6n. A final stage comprises a coefficient multiplier An+1 and an adder 6n+1. The adder 6n+1 sums the output of the coefficient multiplier An+1 and the output of the integrator of the preceding integration stage.

Abstract: Data processing apparatus comprises an array of user-operable controls; proximity sensing apparatus associated with the controls for detecting whether a user's hand is within a predetermined distance of one or more of the controls; a display screen for displaying respective screen icons associated with the controls; and a display processor, responsive to a detection that a user's hand is within the predetermined distance of one of the controls, for altering the screen icon associated with that control.

Abstract: This is a design for a microphone which directly outputs a one-bit digital audio signal. No electronic analogue-to-digital converter is required.

Abstract: An audio signal processor for processing 1-bit signals, comprises an input 40 for receiving a 1-bit signal, means 41, 42 for applying a predetermined filter characteristic to the 1-bit signal whereby the signal is also converted to an n-bit signal where n is greater than one, means 43 for determining the absolute value of the n-bit signal, means 46, 51 for producing a dynamics control signal dependent on the said absolute value, means 48 for applying the dynamics control signal to the 1-bit input signal, and means 49 for requantizing the dynamics controlled signal as a 1-bit signal and shaping the noise in the requantized 1-bit signal. Circuits for producing LOG base 2 and the corresponding anti-log are also disclosed.

Abstract: Audio processing apparatus comprises an audio processor operable to apply audio processing operations to two or more input audio channels; user-operable adjustment controls for adjusting processing parameters associated with the audio processing operations; a display screen for displaying icons representing audio processing operations for each of the input audio channels, the display color of at least a part of an icon being defined by a logical color index; a data array mapping a set of logical color indices to colors for display on the display screen; and a detector for detecting user operation of the adjustment controls associated with an input audio channel and, in response to such a detection, for changing the display color of at least the part of the icon associated with that channel by changing the display color defined in the data array for the corresponding logical color index.

Abstract: Apparatus for storing or transmitting a one-bit digital signal comprises an input inverter for inverting a subset of the data bits of an input one-bit digital signal, to generate a bit-inverted signal; a storage or transmission medium for storing or transmitting the bit-inverted signal; and an output inverter for inverting the subset of the data bits of the bit-inverted signal, to regenerate the input one-bit digital signal.

Abstract: A processing apparatus includes a network of interconnected processors comprising a plurality of signal processors for digitally processing input signals in real time to generate output signals and one or more control processors, each control processor controlling the operation of a plurality of signal processors. The processing apparatus automatically schedules control tasks in a plurality of time slices, where more than one control processor is provided for coordination between control processors, a wired-OR configuration connection can be provided to synchronise the beginning and/or end of the time slices. A control processor can change an address field of microcode instructions of a signal processor for implementing a multiplexer function. A control delay list can be provided for scheduling control task delays.

Abstract: Signal processing apparatus is described in which at least two sets of automated signal processing functions are controlled by stored automation commands, at times dependent upon at least two respective timecode signals which may each be associated with a respective source signal supplied to the signal processing apparatus.

Abstract: Data processing apparatus comprises an array of user-operable controls, the controls being adjustable by movement of a user's hand while touching a control; a detector for detecting when a user's hand is touching a control; a display screen for displaying respective screen icons associated with the controls; and a display processor, responsive to a detection that a user's hand is touching one of the controls, for altering the screen icon associated with that control.

Abstract: An audio signal processor for processing 1-bit signals, comprises an input 40 for receiving a 1-bit signal, means 41, 42 for applying a predetermined filter characteristic to the 1-bit signal whereby the signal is also converted to an n-bit signal where n is greater than one, means 43 for determining the absolute value of the n-bit signal, means 46, 51 for producing a dynamics control signal dependent on the said absolute value, means 48 for applying the dynamics control signal to the 1-bit input signal, and means 49 for requantizing the dynamics controlled signal as a 1-bit signal and shaping the noise in the requantised 1-bit signal. Circuits for producing LOG base 2 and the corresponding anti-log are also disclosed.

Abstract: A 1-bit nth order Delta Sigma Modulator where n is at least one comprises a linear signal processing section (50) which processes the 1-bit signal and produces a p bit output, a filter (52) which filters the p bit signal, an adder (53) a quantizer Q coupled to the output of the adder (53) to quantize a p bit signal to a 1-bit output signal, and a noise shaping section 51 which feeds the 1-bit output signal back to the adder 53.