Updated: Dec 9, 2025 | Source: 2024-2028 Question Pool | Topic: E4C
E4C01E4C

What is an effect of excessive phase noise in an SDR receiver’s master clock oscillator?

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Deep Dive: E4C01

The correct answer is D: It can combine with strong signals on nearby frequencies to generate interference. What is an effect of excessive phase noise in an SDR receiver's master clock oscillator is that it can combine with strong signals on nearby frequencies to generate interference. Phase noise can mix with nearby signals, creating interference. For amateur radio operators, this is important for receiver performance. Understanding this helps when troubleshooting interference.

Why Other Answers Are Wrong

Option A: Incorrect. Limiting ability to receive strong signals isn't the effect - phase noise combines with nearby signals to create interference. Limiting strong signals isn't the effect. Option B: Incorrect. Affecting frequency calibration isn't the primary effect - phase noise combines with nearby signals to create interference. Frequency calibration isn't the effect. Option C: Incorrect. Decreasing third-order intercept point isn't the effect - phase noise combines with nearby signals to create interference. Third-order intercept isn't the effect.

Exam Tip

Excessive phase noise effect = can combine with strong signals on nearby frequencies to generate interference. Think 'P'hase 'N'oise = 'P'roblematic 'N'earby interference. Phase noise can mix with nearby signals, creating interference. Not limiting strong signals, not frequency calibration, not third-order intercept - just interference from nearby signals.

Memory Aid

Excessive phase noise effect = can combine with strong signals on nearby frequencies to generate interference. Think 'P'hase 'N'oise = 'I'nterference. Phase noise can mix with nearby signals, creating interference. Important for receiver performance.

Real-World Example

Excessive phase noise in an SDR receiver's master clock oscillator: It can combine with strong signals on nearby frequencies to generate interference. The phase noise sidebands can mix with nearby strong signals, creating unwanted interference products. This is the effect - interference from nearby signals.

Source & Coverage

Question Pool: 2024-2028 Question Pool

Subelement: E4C

Reference: 2024-2028 Question Pool · E4 - Amateur Practices

Key Concepts

Excessive phase noise SDR receiver Master clock oscillator Combine with strong signals Generate interference

Verified Content

Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E4C topic.