Claims
- 1. An ultrasound receiver assembly for use in a presentation board digitizer system, the receiver assembly comprising:(a) a first ultrasound receiver located adjacent to the surface of the presentation board; and (b) a second ultrasound receiver displaced from said first ultrasound receiver in a direction substantially perpendicular to the surface of the presentation board, said first and second ultrasound receivers being connected so as to generate a total output signal corresponding to the instantaneous sum of the ultrasound signals received at each of said first and second ultrasound receives such that the receiver assembly is most sensitive to ultrasound signals incident from a plane p substantially paralled and immediately adjacent to the presentation board.
- 2. The receiver assembly of claim 1, wherein said first and second receivers are connected in series.
Parent Case Info
This application is a continuation of application Ser. No. 08/811,947, filed Mar. 5, 1997, now U.S. Pat. No. 6,292,177.
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Continuations (1)
|
Number |
Date |
Country |
Parent |
08/811947 |
Mar 1997 |
US |
Child |
09/916558 |
|
US |