Title:
DIGITAL/ANALOG CONVERTING CIRCUIT
Document Type and Number:
Japanese Patent JPH03117215
Kind Code:
A
Abstract:
PURPOSE: To improves S/N by providing an inverter having inverter input and output, first and second D/A converters, and a differential amplifier, including an operational amplifier which combines outputs of both converters by subtrac tion. CONSTITUTION: An output voltage V2 of an inverting D/A converter system is inputted to the negative terminal of an operational amplifier 61 in a differential amplifier 60 through a line 61 and nodes 59 and 53. A ground line 52 of the system 50 is inputted to the positive terminal of the amplifier 61 through a node 54. Further, an output voltage V1 from an operational amplifier 17 is inputted to the positive terminal of the operational amplifier 61 in the differential amplifier 60, from a node 54 through lines 41, 47, and 48. Further, a ground line 42 of a D/A conversion system 40 is inputted to the negative terminal of the operational amplifier 61, from a node 53 through a resistance R6 and a line 68. Subtraction is performed in the operational amplifier 61 by this combination. As a result, the noise is reduced and the precision of conversion is improved.
Inventors:
KUREI SUCHIYUWAATO KUREMENTO
SESHIRU CHIEKO HOO
SESHIRU CHIEKO HOO
Application Number:
JP21725390A
Publication Date:
May 20, 1991
Filing Date:
August 20, 1990
Export Citation:
Assignee:
IBM
International Classes:
H03M1/08; H03M1/06; H03M1/74; (IPC1-7): H03M1/08
Domestic Patent References:
| JPS63256020A | 1988-10-24 | |||
| JPH01165228A | 1989-06-29 |
Attorney, Agent or Firm:
Kiyoshi Goda (5 outside)