초록 ▼

A sound masking apparatus especially useful for setting background noise levels in discrete zones includes a signal source, power amplifier, programmable attenuator and remote control. The remote control is a short range radio transmitter that sends a series of pulses that are decoded to control the

A sound masking apparatus especially useful for setting background noise levels in discrete zones includes a signal source, power amplifier, programmable attenuator and remote control. The remote control is a short range radio transmitter that sends a series of pulses that are decoded to control the attenuator. The attenuator selects among discrete possible volume levels using serially-connected analog multiplexers, the multiplexer-selected lines connecting the signal to a desired part of a resistor network defining voltage dividers. The short range radio control makes a single remote controller operable to control volume levels in any zone of a multiple zone installation without direct access to the signal source, whereby the user can change volume levels in small increments to accomodate changing conditions or preferences and to slowly bring sound masking units to full volume levels.

대표청구항 ▼

A sound masking apparatus, comprising: one or more sound masking units, each unit including: a signal source operable to supply an incoherent electrical signal over a range of audible frequency; a power amplifier and audio transducer adapted to produce an audible sound radiating into a free space de

A sound masking apparatus, comprising: one or more sound masking units, each unit including: a signal source operable to supply an incoherent electrical signal over a range of audible frequency; a power amplifier and audio transducer adapted to produce an audible sound radiating into a free space defined by at least one of floors, walls and ceilings of a structure, the audible sound being produced in response to an electrical signal at an input to said power amplifier; a programmable attenuator connected between the signal source and the power amplifier, the attenuator having means to adjust amplitude of the electrical signal at the input to the power amplifier, the one or more sound masking units being mountable in the structure and the audible sound radiating from the one or more sound masking units defining one or more masking zones; and, a remote controller operable to control operation of the attenuator of one said sound masking unit at a time from a distance, individually, the remote controller being mobile and including means to transmit a short-range radio signal across open air ways to the programmable attenuator, the radio signal adapted to indicate a desired power level and the programmable attenuator including means for receiving and decoding said signal, the programmable attenuator maintaining the desired level after cessation of the radio signal.