We are going to adjust the DC voltage level at the point on the right hand side of the diagram shown as the information signal input. To do this, we need a convenient way of adjusting the DC voltage level applied to the base of the transistor. Fortunately, we have such an adjustment easily available. It is the Carrier Frequency preset. The output frequency is available at the left-hand side of Figure 86 but, to avoid loading due to the oscilloscope, we are going to use the amplified output at tp34 for the frequency measurement.