Editing Capacitive keyboard (patent 3750113) (section)

==Improvements==

<blockquote>
What is claimed as new is:
<br/>
*(1) A data entry comprising in combination a pulse generating means.
**(b) an output terminal.
**(c) a plurality of keys adapted for individual actuation each key having a different significance in the entry of data.
**(d) a corresponding plurality of capacitive elements each connected to a respective key and adapted to have the capacitance modified in accordance with the actuation of the corresponding key for selectively transmitting pulses applied thereto and e addressing means commonly connected to said capacitance elements and to said pulse generating means and output terminal for sequentially applying pulses to said capacitance elements and for applying the selectively transmitted pulses therefrom to said output terminal in a predetermined order.<br/>

*(2) The data entry system of claim 1 above further including low impedance sense amplifier means commonly connected to said capacitance elements through said addressing means for providing an output signal representative of and corresponding to an actuated key.<br/>

*(3) The data entry system of claim 2 above wherein said low impedance sense amplifier means operates in the current amplifying mode.<br/>

*(4) A data entry system comprising in combination a pulse generating means 
**(b) a plurality of keys adapted for individual actuation each key having a different significance in the entry of data 
**(c) a corresponding plurality of capacitive elements each connected to a respective key and adapted to have the capacitance modified in accordance with the actuation of the corresponding key for selectively transmitting pulses applied thereto 
**(d) Input addressing means commonly connected to said capacitance elements and to said pulse generating means for sequentially applying pulses to said capacitance elements in a predetermined order and storage means including a plurality of storage elements each respectively corresponding to a different key coupled to said capacitive elements said storage means operating in synchronism with said input addressing means for applying the output representative of each key to the storage element respectively corresponding thereto.<br/>

*(5) The data entry system of claim 4 above further including hysteresis means coupled to said storage means and responsive to output signals therefrom representing an actuated key for increasing the sensitivity of the capacitive element corresponding to the selected key thereby permitting the transmission of pulses over a wider range of key actuations. <br/>

J. Arthur Cencel<br/>''Capacitive keyboard''</blockquote>