Segmented gain controller

• US 6,535,147 B1
• Filed: 11/16/1999
• Issued: 03/18/2003
• Est. Priority Date: 11/16/1998
• Status: Expired due to Term

• Current Assignee: Elo Touch Solutions, Inc.
• Original Assignee: The Whitaker Corporation (Meggitt PLC)
• Inventors: Masters, Tim, Kent, Joel
• Primary Examiner(s): EDWARDS JR, TIMOTHY
• Application Number:
  US09/440,991
• Time in Patent Office: 1,218 Days
• Field of Search: 341/34, 178/18.04, 345/177
• US Class Current: 341/34
• CPC Class Codes: G06F 3/0436 in which generating transducers and detecting transducers are attached to a single acoustic waves transmission substrate

Abstract

A touch screen includes a transmitter capable of delivering an acoustic signal to the touch screen and a receiver adapted to detect acoustic signals on the touch screen and deliver a first signal representative of the detected acoustic signals. An automatic gain control amplifier has an input, output, and control terminal, and is adapted to receive the first signal on the input terminal and deliver an amplified version of the first signal on the output terminal. The control terminal is adapted to receive a control signal that varies the gain of the amplifier. An analog to digital converter is adapted to receive the amplified first signal and deliver a digital representation thereof. A first circuit is adapted to receive one of the amplified first signal and the digital signal, determine the difference between the received signal and a preselected value, and deliver a control signal to the control input of the amplifier. The control signal has a magnitude responsive to the determined difference.

Claims

1. A touch sensor system for a touch responsive computer interface, comprising:

a touch sensor including a transducer for receiving an acoustic signal and converting the received acoustic signal into an electrical, touch signal having a duration, the transducer including an acoustic signal output and a touch signal output;

an adjustable gain amplifier for amplifying the touch signal, the amplifier including a touch signal input coupled to the transducer touch signal output, a gain control input and an amplified signal output; and

a controller including an amplified signal input coupled to the amplifier amplified signal output and a gain control output coupled to the amplifier gain control input, the controller configured for determining a level of the amplified touch signal and generating and outputting an amplifier gain control signal for adjusting the amplifier gain during the touch signal duration if the amplified touch signal does not meet preselected parameters.

2. A control circuit for a touch sensor system, comprising:

an adjustable gain amplifier for receiving and amplifying a signal having a duration, the amplifier including a gain control input and an amplified signal output; and

a microcontroller including an amplified signal input coupled to the amplifier amplified signal output and a gain control output coupled to the amplifier gain control input, the controller configured for determining a level of the amplified touch signal and generating and outputting an amplifier gain control signal for adjusting the amplifier gain during the signal duration if the amplified touch signal does not meet preselected parameters.

3. A dynamic gain controller, comprising:

a processor;

a memory element coupled to the processor;

an amplified signal input coupled to the processor for receiving an amplified input signal, the amplified input signal having a duration; and

a control signal output coupled to the processor for supplying a gain control signal to an adjustable amplifier;

the memory element including computer code for instructing the processor to determine a level of the amplified signal and generate and output an amplifier gain control signal for adjusting an amplifier gain during the input signal duration if the amplified signal does not meet preselected parameters.

4. A control circuit for a touch sensor system, comprising:

an adjustable gain amplifier for receiving and amplifying a signal having a duration, the amplifier including a gain control input and an amplified signal output; and

a microcontroller including an amplified signal input coupled to the amplifier amplified signal output and a gain control output coupled to the amplifier gain control input, the controller configured for generating and outputting an adjusted amplifier gain control signal for adjusting the amplifier gain during the signal duration based upon a set of predetermined gain correction values.

5. A control circuit for a touch sensor system, comprising:

a processor;

a memory element coupled to the processor;

an amplified signal input coupled to the processor for receiving an amplified input signal, the amplified input signal having a duration; and

a control signal output coupled to the processor for supplying a gain control signal to an adjustable amplifier;

the memory element including a parameters database including predetermined gain correction values and computer code for instructing the processor to generate and output an adjusted amplifier gain control signal for adjusting an amplifier gain during the input signal duration based upon the predetermined gain correction values.