Symmetric Linear Equalization Circuit with Increased Gain

摘要

Circuits providing low noise amplification with continuous time linear equalization are described. An exemplary circuit includes four amplification elements, such as MOS transistors. The amplification elements are arranged in differential pairs, and the differential pairs are cross-coupled with a frequency-dependent coupling, such as a capacitive coupling, to enhance high-frequency gain. The outputs of the amplification elements are combined to provide an output representing inverted and un-inverted sums of differences in the input signals.

主权项

1. An apparatus comprising:
a first amplification element comprising a first pair of complimentary MOS transistors, each of the first pair of complimentary MOS transistors having corresponding gate inputs and source inputs, the MOS transistors configured to receive a first signal representing a first symbol of a codeword at the corresponding gate inputs; a second amplification element comprising a second pair of complimentary MOS transistors having corresponding gate inputs and source inputs, each of the second pair of complimentary MOS transistors configured to receive a second signal representing a second symbol of the codeword at the corresponding gate inputs; a first frequency-dependent circuit configured to cross-couple the first input signal to the corresponding source inputs of the second pair of complimentary MOS transistors; a second frequency-dependent circuit configured to cross-couple the second input signal to the corresponding source inputs of the first pair of complimentary MOS transistors; and, an impedance element connected to the first and second pairs of complimentary MOS transistors, the impedance element configured to generate an amplified codeword identification signal, the first and second amplification elements configured to provide a gain corresponding to a combination of common-source gain and common-gate gain, the common-source gain applied to the corresponding gate inputs of the first and second amplification elements and the common-gate gain applied to the frequency-dependent source inputs of the first and second amplification elements, the amplified codeword identification signal used at least in part to determine a set of output bits represented by the symbols of the codeword.