Patent ID: 9685975
Date: 2017-06-20
CPC Classifications: H03F,H03M

Claim:
1. An apparatus for combining a plurality of inputs, said apparatus comprising: a plurality of input lines that receive a corresponding plurality of input signals that are continuous in time; a first set of ladder networks, each said ladder network in the first set having: a first terminal junction point, a second terminal junction point, an inner junction point, and first and second input junction points, with each of said first and second input junction points either coupled to a different one of the input lines or provided with a zero input signal; a second ladder network having a first terminal junction point, a second terminal junction point, an inner junction point, and first and second input junction points, each coupled to the inner junction point of a different one of the ladder networks in said first set; and an output line coupled to the inner junction point of said second ladder network and providing an output signal that is continuous in time, wherein each of the ladder networks includes a number of reactive impedance segments, with each said reactive impedance segment including: (a) at least one series reactance, (b) at least one shunt capacitive element which at least one of (i) is implemented as a discrete capacitor or (ii) derives from an active device, and (c) a junction point to which the reactance and capacitive element are coupled, wherein at least one of the terminal junction points within each of the plurality of said ladder networks is terminated in a characteristic impedance of said ladder network at said at least one terminal junction point, wherein a signal at the inner junction point of each of said ladder networks comprises a summation of signals provided at the first and second input junction points of said ladder network, so that the signal at the inner junction point of each of the ladder networks in the first set comprises a summation of at least two of the input signals and the signal at the inner junction point of the second ladder network comprises a summation of at least one additional input signal, and wherein said input signals are different continuous-time versions of an underlying discrete-time signal and are combined by said ladder networks according to a weighting that reflects a discrete-time to continuous-time encoding.