Title:
CIRCUIT AND METHOD FOR CONVERSION OF SINGLE-BIT DIGITAL INPUT DATA INTO ANALOG FORM
Document Type and Number:
Japanese Patent JPH0722953
Kind Code:
A
Abstract:
PURPOSE: To filter high frequency noise generated through a sigma-delta (E-A) D/A converter to remove it by connecting one end of a discrete electronic element to an operational amplifier and connecting the other end to a reference voltage source or a ground route. CONSTITUTION: When a signal x(0) 24 is equal to '1' in a 1st time period, a contact S2-26 is connected to the reference voltage source VREF 28. When the signal x(0) 24 is equal to '0', a contact S1-30 is connected to the ground route GND 32 and a capacitor CR 34 is short-circuited during the same time period. In a 2nd time period, the whole electric charge in the circuit is redistributed or transferred so that V0 -36 related to each capacitor 22 becomes V0 =-x(k).(CR/Ci). Total transmission relation becomes V0 =(-C1 /CR).x(O).(C/CR).x(1)--(C3 /CR).x(2).(CN/CR).x(n-1). Thus high frequency noise generated by the Β-Δ D/A converter can be removed by filtering it.
Inventors:
KAARIN DORUU KABURAA
Application Number:
JP3230694A
Publication Date:
January 24, 1995
Filing Date:
March 02, 1994
Export Citation:
Assignee:
ADVANCED MICRO DEVICES INC
International Classes:
H03M1/08; H03H19/00; H03M3/02; (IPC1-7): H03M3/02; H03M1/08
Attorney, Agent or Firm:
Fukami Hisaro (3 outside)
Next Patent: SIGNAL CONVERTER