A sound masking system according to the invention is disclosed in which one or more sound masking loudspeaker assemblies are coupled to one or more electronic sound masking signal generators. The loudspeaker assemblies in the system of the invention have a low directivity index and preferably emit an acoustic sound masking signal that has a sound masking spectrum specifically designed to provide superior sound masking in an open plan office. Each of the plurality of loudspeaker assemblies is oriented to provide the acoustic sound masking signal in a direct path into the predetermined area in which masking sound is needed. In addition, the sound masking system of the invention can include a remote control function by which a user can select from a plurality of stored sets of information for providing from a recipient loudspeaker assembly an acoustic sound masking signal having a-selected sound masking spectrum.

A system, method and program product for generating sound masking in an open-plan space. A method is disclosed that includes: establishing a set of acoustic criteria for the space that specifies minimum output levels at a set of specified frequencies; mixing sound samples to create an audio output stream for use as sound masking when broadcast over at least one speaker using a power amplifier; and processing the audio output stream, wherein the processing includes: analyzing the audio output stream with a spectrum analyzer to determine if the minimum output levels at the set of specified frequencies are met; and level adjusting the audio output stream with an equalizer to ensure that minimum output levels at the set of specified frequencies are met but do not exceed a given threshold above the minimum level.

A jamming device includes a periodic signal generating circuit configured to generate a periodic signal, a noise generating circuit configured to generate a noise signal, and a sweep-signal generating circuit coupled to the periodic signal generating circuit and the noise generating circuit. The sweep-signal generating circuit is configured to generate a frequency-sweep signal based on the periodic signal and the noise signal.

A system for near field communications is provided. The system can include a near field generator configured to generate a near field detectable signal comprising information. The system can include a near field detector configured to receive the near field detectable signal and output the information. The system can include an Electro-Magnetic (EM) shield surrounding the near field generator to block EM radio frequency (RF) signals in the vicinity of the near field generator from interfering with operations of the near field generator. The EM shield does not prevent communication of the near field detectable signal between the near field generator and the near field detector. The EM shield can be configured to reduce magnetic field loss from eddy currents in the EM shield as the near field detectable signal passes through the EM shield.

Disclosed is a radio frequency communication and jamming device configured for physically secured friendly radio frequency communication and for jamming hostile radio frequency communication, the radio frequency communication and jamming device including: an antenna arrangement having a transmission section for transmitting outgoing signals and a receiving section for receiving incoming signals; a receiver device configured for extracting an incoming information signal from the incoming signals received via the receiving section of the antenna arrangement in a receiving frequency band; a jamming generator configured for generating at least one jamming signal for jamming at least one jamming frequency band, wherein the jamming signal is transmitted as one of the outgoing signals via the transmission section, wherein the at least one jamming frequency band includes the receiving frequency band; and a self-interference cancellation device configured for cancelling portions of the at least one jamming signal in the incoming signals received via the receiving section at least in the receiving frequency band.

A jamming or MAS system is provided having multiple transmit antennas for transmitting respective transmit signals with spatial diversity to reduce multipath fading. The jamming or MAS communication system communicates with at least one receiver for receiving the transmit signals with no additional processing required at the receiver. In some embodiments, the jamming or MAS communication system includes an associated receiver for receiving and analyzing various signals. The jamming or MAS communication system in the present invention is able to help reduce the effects of multipath fading without modifications to the receiver. Prior art attempts to reduce the effects of multipath fading require some form of additional processing at the receiver. The invention is particularly useful when deployed in a Managed Access Service (MAS) system or a jamming system. In particular, such a system can be used in a facility (such as a prison, school, government building, etc) to prevent cellphone usage.

A wireless sound-emitting device includes a housing adapted to be coupled to a wall at a source of electric power, a loudspeaker positioned at a periphery of the housing, a control module outputting an electric audio signal to the at least one loudspeaker, and a wireless communications module in electrical communication with the control module. The loudspeaker emits acoustic signals in a direction parallel to the wall, when the housing is coupled to the wall, with the acoustic signals reflecting off the wall. The device may produce a sound masking noise or play a sound recorded on an internal memory. The device may include an electric plug or be adapted to replace an electric outlet faceplate. The device may have electric pass-through outlets and may be powered by the source of electric power. The device may be controlled remotely, for example via an Internet of Things (IoT) platform.

A sound masking system according to the invention is disclosed in which one or more sound masking loudspeaker assemblies are coupled to one or more electronic sound masking signal generators. The loudspeaker assemblies in the system of the invention have a low directivity index and preferably emit an acoustic sound masking signal that has a sound masking spectrum specifically designed to provide superior sound masking in an open plan office. Each of the plurality of loudspeaker assemblies is oriented to provide the acoustic sound masking signal in a direct path into the predetermined area in which masking sound is needed. In addition, the sound masking system of the invention can include a remote control function by which a user can select from a plurality of stored sets of information for providing from a recipient loudspeaker assembly an acoustic sound masking signal having a-selected sound masking spectrum.

A communications system and methods for covert communications are provided. A first transmitter that transmits an information carrying signal to a target receiver, a second transmitter and a third transmitter transmit jamming signals to the target receiver, such that the information carrying signals and the jamming signals are interleaved when received by the target receiver The information carrying signals and the jamming signals can be at least partially overlapping by an eavesdropper.

An RF antenna platform selectively configurable for portable or non-portable use, the platform comprising: a body comprising at least one RF antenna for transmitting and receiving RF signals; at least one component interface provided on the body for interchangeable mounting of different types of stabilising component to the body; wherein the component interface is common to each of the different types of stabilising component such that the portable and non-portable configurations of the platform are selectively determined by the type of stabilising component mounted to the body.