| 摘要 |
PURPOSE: To constitute a digital circuit and to highly accurately establish synchronism by setting a frequency set value by prescribed bit width and outputting a local oscillation signal. CONSTITUTION: Outputs QX, IX from integrators 7a, 7b are given to a CPU 8. The CPU 8 sets a frequency set value consisting of prescribed bit width corresponding to a frequency difference and a phase difference between a spread spectrum signal digitized by an A/D converter 4 and local oscillation signals S1 , S2 . A carrier generator 10 generates a phase value ϕ corresponding to the frequency set point, generates digital local oscillation signals S1 , S2 with amplitude corresponding to the phase value ϕ and gives these signals S1 , S2 to respective 1st multipliers 5a, 5b. When the spread spectrum signal is synchronized with an PN code outputted from a code generator 14 and respective local oscillation signals S1 , S2 , the output IX from the integrator 7b is restored to a correct data signal. At this time, the output QX from the integrator 7a is almost zero. |
