AM Detector

The purpose of this lab was to understand a simple diode detectir circuit, understand a biased diode detector circuit, analyze a complementary feedback pair (CFP), and add the chosen detector circuit to my radio's audio amplifier.

First, I constructed the simple detector circuit. Next, I fed an AM signal to the detector circuit. The results are shown in Figure 1. I was unsuccessful in getting the diode to turn on so I obviously won't use this detector!

Figure 1: Simple Detector Input and Output Signal

Next, I constructed the biased diode detector circuit and fed a suitable AM signal. The results are shown in Figure 2. As amplitude is increased, both input and output increases. You can see a bit of clipping on the signal but I will test it with the LM386 amplifier and see how it sounds before I make a decision on which detector to use.

Figure 2: Biased Diode Detector Input and Output Signal

The final detector that we were to test was the CFP detector. I constructed the circuit and examined the results that are shown in Figure 3. The detector appears to be a bit noisy but I will test it with the LM386 amplifier and see how it sounds.

Figure 3: CFP Detector Input and Output Signal

Finally, I decided to test both the biased diode detector and the CFP detector with the LM386 amplifier. I then chose based on which combination sounded better. I chose the CFP detector with the LM386 because it was a very loud, clear noise.