diode = 1N4150
R = 1.2 k


                        o----|>|-----------+---------o
FG (sine, 2.0 Vpp, 1000 Hz)                |
           or                              R              Scope
FG (ramp, -1 to 1 V, 200 Hz)               |
                        o------------------+---------o

                        o--------+---|>|---+-------+---------o
                                 |         |       |
                                 +---|<|---+       |
FG (sine, 2.0 Vpp, 1000 Hz)                        |
           or                                      R              Scope
FG (ramp, -1 to 1 V, 200 Hz)                       |
                                                   |
                        o--------------------------+---------o