Deep Dive: E7F11
The correct answer is B: Reference voltage level and sample width in bits. What sets the minimum detectable signal level for a direct-sampling software defined receiver in the absence of atmospheric or thermal noise is reference voltage level and sample width in bits. ADC resolution and reference voltage determine minimum detectable signal. For amateur radio operators, this is important for SDR technology. Understanding this helps when working with SDRs.
Why Other Answers Are Wrong
Option A (Sample clock phase noise): Incorrect. Sample clock phase noise doesn't set minimum signal - reference voltage and sample width do. Phase noise isn't the factor. Option C (Data storage transfer rate): Incorrect. Data storage transfer rate doesn't set minimum signal - reference voltage and sample width do. Transfer rate isn't the factor. Option D (Missing codes and jitter): Incorrect. Missing codes and jitter don't set minimum signal - reference voltage and sample width do. Missing codes/jitter aren't the factors.
Exam Tip
Minimum detectable signal level in direct-sampling SDR = reference voltage level and sample width in bits. Think 'M'inimum 'S'ignal = 'R'eference 'V'oltage and 'B'its (ADC resolution). ADC resolution and reference voltage determine minimum detectable signal. Not phase noise, not transfer rate, not missing codes/jitter - just reference voltage and sample width.
Memory Aid
Minimum detectable signal level in direct-sampling SDR = reference voltage level and sample width in bits. Think 'M'inimum 'S'ignal = 'R'eference + 'B'its. ADC resolution and reference voltage determine minimum detectable signal. Important for SDR technology.
Real-World Example
The minimum detectable signal level for a direct-sampling SDR receiver: It's set by the reference voltage level and sample width in bits. The ADC's resolution (bits) and reference voltage determine the smallest signal that can be detected. This is what sets it - reference voltage and sample width.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E7F
Reference: 2024-2028 Question Pool · E7 - Practical Circuits
Key Concepts
Verified Content
Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E7F topic.