| 摘要 |
PURPOSE:To eliminate the need for any delicate adjustment by providing a means rectifying each low frequency component, comparing the quantity and outputting a larger signal level as an envelope detection output. CONSTITUTION:One signal output of a distributor 11 is fed to a distributor 12, where the signal is distributed into two; one output is subject to phase correction at a phase shifter 15 and multiplied with an output of a comparator 13 by a multiplier 17. The other output of the distributor 12 is subject to phase correction by a phase shifter 16 and multiplied with the output of a delay line 14 at a multiplier 18. The phase shifters 15, 16 are corrected so that the phase of the signals inputted to the multipliers 17, 18 is in phase. The output of the multipliers 17, 18 is supplied to LPFs 19, 20, from which only the low frequency component is extracted. The output is subject to full wave rectification by a quantity comparison detection circuit 13, the larger level signal is detected as the output to obtain a correct envelope component. Further, the delay element 14 retards a binary signal being the output of the comparator 13, and no analog delay line is required and the circuit constitution is simplified. |
