As in Practical Exercise 7.15, we are going to use the Carrier Frequency preset to vary the input voltage to the base of the modulating transistor. To avoid loading due to the oscilloscope, we are again going to use the amplified output at tp34 for the frequency measurement. Ensure that the Carrier Frequency preset in the Reactance Modulator is set to its fully clockwise position. Record in your workbook the oscillator output frequency measured at tp34 and the DC input voltage measured at tpl Turn the Carrier Frequency preset to its fully counter-clockwise position. Again record in your workbook the oscillator output frequency measured at tp34 and the DC input voltage measured at tp11. If you have a frequency meter available, it could be used to take a series of readings as the preset is adjusted to enable a graph of DC voltage/frequency output to the plotted. The result would be similar to that shown in Fiomme 95 below.