US 4,381,495 AGranted

Digital-to-analog converter with error compensation

AssigneeHitachi, Ltd.

InventorsMasao Hotta, Kenji Maio, Norio Yokozawa, Hiromi Nagaishi

Life of this patent

Estimating the term…

Loading patent…

Abstract

A digital-to-analog conversion system includes a digital-to-analog converter, a source of at least one set of digital input signals and a signal for error compensation and a digital signal for error detection to the converter, a switch to selectively couple either the one set of digital input signals and the signal for error compensation or the signal for error detection to the converter, a clock to generate a switching signal having a predetermined period and duration which is coupled to control the switch, a distribution switch for selectively coupling the output of the digital-to-analog converter to two different terminals, receiving a control input from the clock, a sample and hold circuit to sample and hold the output of the digital-to-analog converter, a detector for detecting a linearity error in the digital-to-analog converter output signal when the digital signal for error detection is coupled as an input thereto, a memory for storing the output of the detector, a circuit to write the output of the detector into the memory, and a circuit to read the data from said memory and couple it as the signal for error compensation at the input to the digital-to-analog converter.

Claims6

Dependent claims

A digital-to-analog conversion system comprising:

(a) a digital-to-analog converter;
(b) means for selectively supplying to said analog digital converter:
(i) at least one set of digital input signals and a signal for error compensation;
and
(ii) a digital signal for error detection;
(c) means to selectively couple either said one set of digital input signals and said signal for error compensation or said signal for error detection to said converter;
(d) means to generate a switching signal having a predetermined period and duration, said switching signal coupled to control said means to selectively couple to thereby cause it to alternately couple said one set of digital input signals and said signal for error compensation and said signal for error detection to said converter;
(e) distribution means for selectively coupling the output of said digital-to-analog converter to two different terminals, said means receiving a control input from said means to generate;
(f) means coupled to one of said terminals to sample and hold the output of said digital-to-analog converter;
(g) means for detecting a linearity error in said digital-to-analog converter output signal when said digital signal for error detection is coupled as an input thereto, coupled to the other terminal of said means to couple the input;
(h) a memory for storing the output of said means for detecting an error;
(i) means to write the output of said means for detecting into said memory;
and
(j) means to read the data from said memory and couple it as the signal for error compensation at the input to said digital-to-analog converter.

11 more elements

Dependencies are inferred from the claim text.