Classical quantum computer is an analog probabilistic computer. The digital quantum computer that can be implemented in FPGA has been described in the article. Digital quantum coprocessor is designed to implement algorithms for execution on the analog quantum computers. A digital quantum coprocessor operates under the control of a classical computer and together they are digital quantum computer. The digital quantum coprocessor is a set of digital units called digital qubits that have multi-bit data input and single-bit data output each. The digital qubit is a wave function calculator.