An electronic device or method for adjusting a gain on a voice operated control system can include one or more processors and a memory having computer instructions. The instructions, when executed by the one or more processors causes the one or more processors to perform the operations of receiving a first microphone signal, receiving a second microphone signal, updating a slow time weighted ratio of the filtered first and second signals, and updating a fast time weighted ratio of the filtered first and second signals. The one or more processors can further perform the operations of calculating an absolute difference between the fast time weighted ratio and the slow time weighted ratio, comparing the absolute difference with a threshold, and increasing the gain when the absolute difference is greater than the threshold. Other embodiments are disclosed.

In the field of communications assemblies, particularly those arising in connection with high voltage direct current (HVDC) power converters, there is provided a communications assembly (10) that comprises a first module (12) which is arranged in operative communication with a second module (14A, 14B, 14C, 14D, 14E, 14F, 14G, 14H) via a communication conduit (16A, 16B, 16C, 16D, 16E, 16F, 16G, 16H). At least one of the first module (12) and the second module (14A, 14B, 14C, 14D, 14E, 14F, 14G, 14H) have a receiver (24) that includes a squelch filter (26) which is configured to operate in a first normal mode and a second test mode. The squelch filter (26) normally operates in the first normal mode to suppress a signal output (28) from the receiver (24) when the strength of an input signal (30) received by the receiver (24), via the communication conduit (16A, 16B, 16C, 16D, 16E, 16F, 16G, 16H), falls below a normal threshold. The squelch filter (26) selectively operates in the second test mode to suppress the signal output (28) from the receiver (24) when the strength of the input signal (30) received by the receiver (24), via the communication conduit (16A, 16B, 16C, 16D, 16E, 16F, 16G, 16H), falls below a test threshold higher than the normal threshold. When the squelch filter (26) is operating in the second test mode, a signal output (28) from the receiver (24) indicates a signal margin in the communication conduit (16A, 16B, 16C, 16D, 16E, 16F, 16G, 16H) that is at least equal to the difference between the test threshold and the normal threshold.

To control loudness during a junction between different types of broadcast content, such as a junction between programme and commercial or promotional content, representative loudness values for content respectively before (P) and after (C) the junction are received from a playout automation system. A time-varying gain control is applied before and after the junction in order to smooth loudness around the junction. The audio gain is smoothly increased prior to the junction to a gain (P+C)/2P times higher than the original gain value. Then, the gain is reduced shortly before the junction to a value (P+C)/2C times lower than the original gain value. After the junction, the gain is returned smoothly to the original value.

Systems and methods for handling silence in audio streams are disclosed. In one aspect, a transmitter detects a halt in an audio stream. After detection of the halt in the audio stream, the transmitter embeds a silence signal into the audio stream and transmits the silence signal to associated receivers. The associated receivers may respond to the embedded silence signal by “playing” silence or by using the silence signal to activate a silence protocol. In either event, the associated receivers do not receive the original audio halt and do not produce an unwanted audio artifact.

This application describes methods and apparatus for selectively clamping a signal path (106) for an analogue audio signal to a clamp voltage, e.g. ground. Voltage clamping circuitry (200) is disclosed having a first switching device (201) in series with a second switching device (202) between a node of the signal path and the clamp voltage. The clamping circuitry is configured to be operable in: a first state where the first and second switching devices are both on to electrically connect the signal path to the clamp voltage; and also a second state to electrically disconnect the signal path from the clamp voltage. In the second state one of the first and second switching devices is configured to block conduction when the voltage at said node of the signal path is positive and the other switching device is configured to block conduction when the voltage at said node of the signal path is negative.

A squelch detector, including: an input configured to receive an input signal; a peak detector connected to the input configured to detect a maximum value of the input signal wherein the peak detector includes a refresh input configured to receive a refresh signal to refresh the output of the peak detector, a valley detector connected to the input configured to detect a minimum value of the input signal wherein the valley detector includes a refresh input configured to receive the refresh signal to refresh the output of the valley detector, and a comparator including a first signal input connected to an output of the peak detector, a second input connected to an output of the valley detector, and a first reference input, wherein the comparator is configured to compare a difference between an output of the peak detector and an output of the valley detector and a reference value received at the first reference input and configured to produce an output based upon the comparison.

Provided is a remote broadcast system including an audio amplifier activation device configured to turn on when a level of input sound via a smartphone mobile unit exceeds a threshold, a power source for an audio amplifier configured to amplify a signal of the input sound into a broadcast audio signal, and output the broadcast audio signal to a broadcast loudspeaker, the audio amplifier activation device being configured also to turn off the power source for the audio amplifier when the level of the input sound remains lower than the threshold for a predetermined time period. A broadcaster carrying a smartphone base unit can select a smartphone mobile station via the smartphone base unit, and establish a communication link between the smartphone base unit and the smartphone mobile station. With this, the broadcaster is allowed to broadcast evacuation guidance information even while evacuating.

A voltage clamping circuit is provided. In an embodiment, the voltage clamping circuit includes a plurality of gain shifting circuits and a signal processing circuit. The plurality of gain shifting circuits receive an input voltage and voltage levels to generate a plurality of shifted voltages. The signal processing circuit generates a difference value of the plurality of shifted voltages to generate an output voltage according to the difference value, such that the voltage clamping circuit achieves an implementation of a passing band or a rejection of the input voltage.

A power amplifier includes a digital-to-analog converter, a loop filter, a driver circuit, a first adjustable reference resistor and a second adjustable reference resistor. A circuit includes an overcurrent protection circuit and a power amplifier, wherein the overcurrent protection circuit is communicatively coupled to the power amplifier. The digital-to-analog converter is configured to receive a digital signal and to output an analog signal, the driver circuit communicatively coupled to the loop filter and at least one of a first output port and a second output port of the power amplifier.

A power amplifier includes a digital-to-analog converter, a loop filter, a driver circuit, a first adjustable reference resistor and a second adjustable reference resistor. A circuit includes an overcurrent protection circuit and a power amplifier, wherein the overcurrent protection circuit is communicatively coupled to the power amplifier. The digital-to-analog converter is configured to receive a digital signal and to output an analog signal, the driver circuit communicatively coupled to the loop filter and at least one of a first output port and a second output port of the power amplifier.