Ultrasonic digitizer and host

Abstract

A computing system comprises a processor and internal peripheral devices, and a system bus connecting the internal peripheral devices to the processor. One of the internal peripheral devices is an ultrasonic digitizer that digitizes ultrasonic signals from at least two associated microphones into a digitized audio signal carrying a corresponding location and outputs the digitized audio as a signal on the system bus.

What is claimed is: 
     
         1 . A computing system for determining a location of a positioning device, the computing system comprising:
 a processor having a system clock;   a CODEC external to said processor, said CODEC being configured to decode ultrasonic signals of said positioning device received via at least two microphones to provide said processor with a positioning signal further processable to determine said location; and   a synchronizing unit for synchronizing said CODEC with said system clock.   
     
     
         2 . The computing system of  claim 1 , further comprising a filter in parallel with said CODEC. 
     
     
         3 . The computing system of  claim 1  wherein:
 said CODEC is further configured to determine a time of flight of each of said ultrasonic signals; and 
 the processor is configured to determine said location based on triangulation using said time of flight of each of said ultrasonic signals. 
 
     
     
         4 . The computing system of  claim 1  wherein said ultrasonic signals comprise a location signal modulated onto a continuous ultrasonic carrier. 
     
     
         5 . The computing system of  claim 1 , further comprising a screen and wherein said at least two microphones are fixed about said screen to provide a touchscreen application. 
     
     
         6 . The computing system of  claim 1 , further comprising a wireless transceiver for wireless networking, wherein said synchronization unit further synchronizes said wireless transceiver with said system clock. 
     
     
         7 . The computing system of  claim 1 , further comprising:
 an accommodation assembly for accommodating paper in a defined relationship with said computing system; and   a housing, wherein said paper accommodation system comprises a paper alignment structure, said paper alignment structure comprising a configuration that holds paper in a fixed relationship with said at least two microphones.   
     
     
         8 . The computing system of  claim 7  wherein said paper alignment structure is built onto said housing. 
     
     
         9 . The computing system of  claim 7  wherein said paper alignment structure comprises a first set of at least two microphones about one side thereof and a second set of at least two microphones about a second side thereof and a selector for selecting between said first and said second sets of at least two microphones depending on which set are receiving a clearer signal. 
     
     
         10 . The computing system of  claim 1 , further comprising a housing, wherein said housing comprises a recharging holder for said positioning device. 
     
     
         11 . The computing system of  claim 1 , further comprising a third microphone for three-dimensional location of said positioning device. 
     
     
         12 . The computing system of  claim 11  configured to use said three-dimensional location to compensate for a height of paper in determining said location. 
     
     
         13 . The computing system of  claim 1  configured such that activation of said positioning unit switches said computing system from a dormant state to an active state. 
     
     
         14 . The computing system of  claim 1 , further comprising a positioning unit comprising a memory that stores user input while said computing system is in a dormant state, which user input is subsequently accessible by said computing system. 
     
     
         15 . The computing system of  claim 1 , further comprising a positioning unit configured to accept input while said computing system remains in an otherwise dormant state. 
     
     
         16 . The computing system of  claim 1 , further comprising a computer housing and wherein said at least two microphones are in a fixed relationship with respect to said housing. 
     
     
         17 . The computing system of  claim 1 , further comprising a system bus coupled to said processor, wherein said positioning signal is sent to said processor using said system bus. 
     
     
         18 . A method of determining a location of a positioning device, the method comprising:
 receiving ultrasonic signals from said positioning device using at least two microphones;   decoding said ultrasonic signals using an external CODEC to generate a positioning signal;   processing said positioning signal to determine said location of said positioning device; and   synchronizing said external CODEC with a processor clock.   
     
     
         19 . The method of  claim 18 , further comprising filtering said ultrasonic signals in parallel with said decoding. 
     
     
         20 . The method of  claim 18  wherein determining said location of said positioning device comprises:
 determining a time of flight of each of said ultrasonic signals; and 
 determining said location based on triangulation using said time of flight of each of said ultrasonic signals. 
 
     
     
         21 . The method of  claim 18 , further comprising outputting said positioning signal over a bus to a processor, wherein said processor performs said processing. 
     
     
         22 . A computing system comprising:
 processing means having a clock; and   decoding means external to said processing means, said decoding means comprises a synchronizing means;   wherein said decoding means comprises means for decoding ultrasonic signals received from a positioning means via at least two sensing means and means for providing said processing means with a positioning signal;   wherein said processing means comprises means for processing said positioning signal to determine a corresponding positioning device location; and   wherein said synchronizing means comprises means for synchronizing said decoding means with said clock.   
     
     
         23 . The computing system of  claim 22 , further comprising a filtering means in parallel with said decoding means. 
     
     
         24 . The computing system of  claim 22 , further comprising a display means and wherein said at least two sensing means are fixed about said display means to provide a touchscreen application. 
     
     
         25 . A computing system comprising:
 a processor having a clock;   internal peripheral devices;   a CODEC external to said processor; and   a system bus connecting said internal peripheral devices to said processor;   wherein:
 one of said internal peripheral devices is configured to receive information associated with ultrasonic signals from at least two associated microphones and output a digitized audio output as a signal on said system bus; 
 said digitized audio output comprises a decoded positioning device location; 
 said one of said internal peripheral devices is coupled to said CODEC to use said CODEC to decode said location; and 
 said CODEC is synchronized with said clock. 
   
     
     
         26 . The computing system of  claim 25 , further comprising a filter in parallel with said CODEC. 
     
     
         27 . The computing system of  claim 25  wherein said ultrasonic signals comprise a location signal modulated onto a continuous ultrasonic carrier. 
     
     
         28 . The computing system of  claim 25 , further comprising:
 a wireless unit configured for wireless networking; and   a synchronization unit configured to synchronize said CODEC with said clock and synchronize said wireless unit with said clock.