A method for generating, by an electrical device based on an input signal, an output signal that exhibits a negative group delay. The method includes the following steps, carried out by a programmable digital processing unit of the device: obtaining a sampling frequency associated with a digital signal representative of the input signal; obtaining a target negative group delay value; determining a set of coefficients for a differential equation according to the sampling frequency and the target negative group delay value; calculating, upon acquiring a current value of the digital signal, a corresponding current value of the output signal by using the differential equation.

A delay line is constructed by combining a phase generator and a fabric. The phase generator splits a digital input signal in multiple incrementally delayed versions, which are input to the fabric. The fabric has an array of node filters. Inputs of filters in the first array column are inputs of the fabric. A node filter has a delay element and a cross-coupling element, whose output signals are added or subtracted to form a filter output signal. A node filter in a row is concatenated to the previous filter in the row through its delay element. Inputs of cross-coupling elements are connected to other array rows. Outputs of node filters form the outputs of the fabric. Delay times of delay elements and cross-coupling elements are nominally equal. Drive strengths of cross-coupling elements may be lower than drive strengths of delay elements.

A phase shifter for altering the phase of a radio frequency signal is disclosed herein. A Lange coupler is used having reflective ports that are coupled to artificial transmission lines. The artificial transmission lines provide a reflection transmission path, the length of which can be determined by digital control lines. Transistors placed along the length of the central trace provide independent paths to ground that serve to shorten the electrical length of the ATL. Accordingly, by selectively turning the transistors on/off, the electrical length of the ATL can be selected and thus the amount of phase delay introduced by the phase shifter.