Spectral shaping of circuit errors in digital-to-analog converters

A digital-to-analog converter having a digital input representing a value and a single analog output, where said analog output is an analog equivalent of the input, said converter comprising:

• at least one switching block layer interposed between said input and said output, each switching block layer containing at least one switching block having an input signal x.sub.k,r ›n!, and two output signals, x.sub.k-1,2r-1 ›n! and x.sub.k-1,2r ›n!, wherein each output signal has a value in the range {0, 1, . . . , 2.sup.k-1 }, and x.sub.k,r ›n!=x.sub.k-1,2r-1 ›n!+x.sub.k-1,2r ›n!, where k is the layer number and r identifies the switching block in the layer;
• a plurality of digital-to-analog converters (DACs) each having an input and an output, said input to each DAC connected to receive one of said outputs of one of said switching blocks in the last switching block layer, where said output of each DAC is an analog equivalent of said input;
• and
• an output adder connected to receive said outputs of each DAC, wherein said output adder combines said DAC outputs into said single analog output.

An element of a recursive digital-to-analog converter wherein each element is a digital-to-analog converter comprising:

• a switching block interposed between said input and said output, said switching block having an input signal and first and second output signals of k bits, wherein each output signal has a value in the range {0, 1, . . . , 2.sup.k-1 }, and wherein said input signal equals a sum of said output signals;
• a first digital-to-analog converter (DAC) having an input and an output, said input to said first DAC connected to receive said first output of said switching block, where said output of said first DAC is an analog equivalent of said input;
• a second DAC having an input and an output, said input to said second DAC connected to receive said second output of said switching block, where said output of said second DAC is an analog equivalent of said input;
• and
• an adder connected to receive said outputs of said first and second DAC, wherein said adder combines said DAC outputs into said single analog output.

A method of achieving digital-to-analog conversion, the method comprising the steps of:

• (a) receiving a digital input signal in a first switching block layer of a plurality of switching block layers;
• (b) splitting the digital signal into two output signals, wherein each of the two output signals has a value in the range {0, 1, . . . , 2.sup.k-1 }, where k is a layer number, and wherein a sum of the output signals equals the digital input signal;
• (c) repeating steps (a) and (b) for each of said plurality of switching block layers, where the output signals of a k layer are the digital input signals for a k-1 layer;
• (d) converting output signals of a last switching block layer into a plurality of analog signals;
• and
• (e) combining the plurality of analog signals into a single converted signal.

A method of achieving digital-to-analog conversion, the method comprising the steps of:

• (a) receiving a digital input signal in a switching block, where said input signal is a k+1 bit signal;
• (b) splitting the digital signal into two output signals, wherein each of the two output signals has a value in the range {0, 1 . . . , 2.sup.k-1 }, where k is the number of bits of each output signal, and wherein a sum of the output signals equals the digital input signal;
• (c) converting said output signals into a first analog signal and a second analog signal;
• and
• (d) combining the first and second analog signals into a single convened signal.