The diagram in Fig. 8C9 shows a simplified...

Question 1 of 27070xDDEYtRHhWDuONugm0IH

The diagram in Fig. 8C9 shows a simplified RADAR mixer circuit using a crystal diode as the first detector. What is the output of the circuit when no echoes are being received?

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Question 1 of 27070

The diagram in Fig. 8C9 shows a simplified RADAR mixer circuit using a crystal diode as the first detector. What is the output of the circuit when no echoes are being received?

🔍 Key Concepts

• Mixer circuits in marine radar – how the received echo signal and local oscillator signal combine in a nonlinear device (diode) • Intermediate frequency (IF) – the difference between the transmitted/local oscillator frequency and the received echo frequency • What happens in a mixer diode when one of the inputs (echo) is missing

💭 Think About

• Think about what a mixer actually produces from its inputs – sum and difference frequencies of the signals fed into it. What signals are present when there is no echo? • Is there still any RF or local oscillator signal at the mixer, even when no targets are present on the scope? How does that affect the output? • Consider whether the crystal diode can generate an output IF frequency with only one signal applied instead of two.

✅ Before You Answer

• Identify which frequency in the choices looks like a difference (IF) frequency between the radar operating frequency and the local oscillator frequency typically used in X‑band radar problems like this. • Decide whether a continuous-wave (CW) output can exist at the IF if only the local oscillator is present at the mixer input. • Confirm whether a nonlinear device like a diode mixer can produce the stated outputs without a second input signal (the echo).