| 摘要 |
PURPOSE:To not only reduce the power consumption but also miniaturize a device with one high frequency mixer by inputting a reception signal and the output of a local oscillator, which is deviated from its reception frequency by a maximum frequency deviation value of modulation, to one high frequency mixer to perform frequency conversion. CONSTITUTION:A high-frequency reception signal R(t) received by an antenna 1 is amplified by a low-noise amplifier 8 and is mixed with the output from a local oscillator 2 by a high frequency mixer 3 and is converted to a base band signal. A component of a frequency 2fc is eliminated by a low-pass filter 4 whose band width 2fd is about two times as wide as a modulation frequency fd,and the output of the filter 4 is amplified by an amplifier 9, and the output of this amplifier 9 is inputted to a differentiator 5. The output of the differentiator 5 is squared by a detector 6 using the nonlinear area of a diode and is inputted to a low-pass filter 7 and has a component of a frequency 4fd eliminated by the filter 7 and is discriminated in a comparator 10 based on a set threshold to obtain a reproduced binary code. |
