Ericsson Gmbh

Diagraph Corporation

Ronald J Johnsen

Jimmy L Droit

Mark K Virkus

Mark V Reinders

Paul W Dent

Matthew Justin Murray

Jim Agne Rasmusson

A buzzer assembly for a personal communications device changes geometry in order to emit sounds at a variety of frequencies at an approximately constant volume, such as for playing melodic alerts. The buzzer assembly incorporates a buzzer and gasket to create an air chamber with an associated acoustic impedance. A translational actuator moves a portion of either the buzzer or gasket, depending on the particular embodiment, to change the air volume and thus the associated acoustic impedance. By changing the acoustic impedance, the resonant frequency of the buzzer assembly is changed. When the buzzer is then operated at or near resonant frequency corresponding to the then-current acoustic impedance, the sound generated by the buzzer assembly is louder. By changing the resonant frequency of the buzzer assembly in this manner to correspond to the frequency of the tone to be generated, the sound volume generated by the buzzer assembly can be made approximately constant across a broader frequency range than is possible with conventional buzzer designs, such as 3 kHz or larger.

Variable frequency buzzer assembly

A system for ink jet printing of messages on articles being fed forward one after another in a predetermined path. A terminal includes a keyboard for entering message data representative of the messages. A controller interconnected with the terminal processes the message data received from the terminal and stores the message data for the messages. The controller has an output port for providing serial output data in a bit map format representative of the messages. A plurality of ink jet printheads are serially connected and positioned adjacent the path of the articles to print the messages on the articles in response to the serial output data. A single cable connects the output port of the controller to the first printhead for providing the output data to the first printhead. A separate cable interconnects each printhead to its next succeeding printhead for serially providing the data to the remaining printheads so that the printheads are connected in a daisy chain configuration. Power is also supplied to the printheads in a daisy chain configuration.

Ink jet system with serial data printheads

In an audio system, a loudspeaker responds to an input signal producing a sound pressure wave having a linear component, which is linear function of the input signal, and an undesired non-linear component, which is a non-linear function of the input signal. Accordingly, it is desirable to reduce the non-linear component of the output sound pressure wave. An adaptive precompensating audio system for reducing this non-linear component includes a loudspeaker for producing a sound pressure wave and a precompensating filter for precompensating an input signal representative of the desired sound pressure wave. In addition, a microphone may be used to convert the resulting sound pressure wave into a sound signal and a precompensating filter modifier may be used to modify the precompensating filter in response to the sound signal. Preferably, the precompensating filter transforms the input signal using an inverse of an estimated transfer function for the loudspeaker.

Apparatus and method for adaptively precompensating for loudspeaker

Growing community of inventors

Cary, NC, United States of America

Ronald J Johnsen