How to build Frequency Doubler with 4011

Description

This frequency doubler uses one CMOS quad, two input NAND gate package type 4011. The frequency doubler proper consists of an inverter IC1B, two differentiating networks R1/C1, R2/C2 and NAND gate IC1A, IC1C and IC1D function as input and output buffers. In Fig.2 exist the pulses in different points of circuit.

Circuit diagrams

circuit from http://users.otenet.gr/~athsam/frequency_doubler_with_4011.htm