Find ratio of R2R1such that vout = 3(vin), since maximum vin provided by the DAC is 5 V and maximum desired vout is 15 V for supplying the JSPHS-1000+ Phase Shifter’s control voltage. Therefore, we would need a voltage gain of Av = vout/vin = 3 V/V. However, this voltage gain is the absolute minimum we would need, so we have actually chosen to increase our desired Av to 5 V/V to compensate for any potential loss. From these assumptions and calculations, we concluded that any value may be selected for R1 and R2, as long as the ratio of R2R1 is equal to 4. We did note the values of R1 and R2 will also vary the value of the current leading into the Bias pins of our JSPHS-1000+ phase shifters. Since the DC input resistance at the Control port, or Bias pins, of these phase shifters is typically 18200 ohms2 , this means the minimum current required would be equal to (15 V / 18200 ohms), or roughly 0.8 mA. The typical output current provided by the LM7358 operational amplifiers ranges from 10 to 20 mA3 , which means any amplifier configuration will satisfy the necessary input Bias current of 0.8 mA for the phase shifters. Knowing this, and given that we are using ¼ W resistors, we have chosen R1= 8 kohms and R2 = 32 kohms. In order to validate our results even further, we conducted another test with our final amplifier configuration and recorded the input/output voltage values and gain.

Results