Envelope modulator for haptic feedback devices

• US 20030057934A1
• Filed: 07/29/2002
• Published: 03/27/2003
• Est. Priority Date: 07/17/2001
• Status: Active Grant

• Current Assignee: Immersion Corporation
• Original Assignee: Immersion Corporation
• Inventors: Tierling, Kollin M.
• Granted Patent: US 7,154,470 B2
• Time in Patent Office: Days
• US Class Current: 324/76.12
• CPC Class Codes: G06F 3/016 Input arrangements with force or tactile feedback as computer generated output to the user
• CPC Class Codes: H03C 1/36 by means of semiconductor device having at least three electrodes H03C1/34, H03C1/50, H03C1/52, H03C1/62 take precedence

Abstract

An amplitude modulator circuit includes a reference oscillator and an envelope modulator coupled to the reference oscillator for receiving a reference signal. A microcontroller is coupled to the envelope modulator for providing an envelope signal to the envelope modulator and a low pass filter is coupled to the envelope modulator for receiving a modulated command from the envelope modulator. An inverter is coupled to the low pass filter for receiving a low passed envelope modulated signal from the low pass filter and a transducer or amplifier is coupled to the inverter and the low pass filter for receiving an inverted low passed signal and the low passed envelope modulated signal.

Claims

1. An amplitude modulator circuit comprising:

A reference oscillator;

An envelope modulator coupled to the reference oscillator for receiving a reference signal;

A microcontroller coupled to the envelope modulator for providing an envelope signal to the envelope modulator;

A low pass filter coupled to the envelope modulator for receiving a modulated command from the envelope modulator;

An inverter coupled to the low pass filter for receiving a low passed envelope modulated signal from the low pass filter; and

A transducer or amplifier coupled to the inverter and the low pass filter for receiving an inverted low passed signal and the low passed envelope modulated signal.

2. An amplitude modulator circuit in accordance with claim 1 wherein the reference oscillator comprises a sine wave generator.

3. An amplitude modulator circuit in accordance with claim 1 wherein the envelope modulator comprises a ramp generator circuit.

4. An amplitude modulator circuit in accordance with claim 1 wherein the low pass filter is a second order low pass filter.

5. An amplitude modulator circuit for use with haptic feedback interface devices, the circuit comprising:

A reference oscillator comprising a sine wave generator;

An envelope modulator comprising a ramp generator circuit coupled to the reference oscillator for receiving a reference signal;

A microcontroller coupled to the envelope modulator for providing an envelope wave shape signal to the envelope modulator;

A low pass filter coupled to the envelope modulator for receiving a modulated command from the envelope modulator;

An inverter coupled to the low pass filter for receiving a low passed envelope modulated signal from the low pass filter; and

A transducer or amplifier coupled to the inverter and the low pass filter for receiving an inverted low passed signal and the low passed envelope modulated signal.

6. An amplitude modulator circuit in accordance with claim 5 wherein the low pass filter is a second order low pass filter.

7. A method of amplitude modulation of a resonant frequency sinusoid by a pulse width modulated envelope function, the method comprising:

providing an envelope wave shape to an envelope modulator;

providing a sinusoidal reference signal to the envelope modulator;

providing a modulated command from the envelope modulator to a low pass filter;

providing a low passed modulated command signal from the low pass filter to an inverter and a transducer or amplifier; and

providing an inverted low passed modulated command signal from the inverter to the transducer or amplifier. passed modulated command signal.

8. A method in accordance with claim 7 wherein the reference oscillator comprises a sine wave generator.

9. A method in accordance with claim 7 wherein the envelope modulator comprises a ramp generator circuit.

10. A method in accordance with claim 7 wherein the low pass filter is a second order low pass filter.