SIGNAL SOURCE PROVIDED WITH POLYPHASE FILTER

摘要

PROBLEM TO BE SOLVED: To provide a signal source for supplying a signal having a frequency that does not have higher harmonics related to the frequency of a local oscillator. SOLUTION: This signal source (S) is provided with the local oscillator (5) for generating a reference frequency signal Fo. The signal source is provided with a 1:N frequency divider (6) connected to the local oscillator, the frequency divider supplies two orthogonal square wave signals (Id and Qd) of a frequency Fo/N and here, the N is equal to 2 or 4×n and the (n) represents an integer. The signal source is further provided with a polyphase filter (7), the polyphase filter supplies two sine orthogonal signals (Is and Qs) being equal to m×Fo/N on the basis of the orthogonal signals (Id and Qd) supplied from the frequency divider and here, the (m) represents an odd number. This signal source is applied to a direct frequency conversion circuit and a transmitting circuit used in the field of telecommunications.