Logic circuits
What is a typical use of a linear feedback shift register (LFSR), which feeds the XOR of some outputs of a shift register back to its input?
- AGenerating pseudo-random patterns, such as test patterns, and computing CRCs
- BMeasuring precise time
- CAmplifying analog signals
Show answer and explanation
Answer: A. Generating pseudo-random patterns, such as test patterns, and computing CRCs
With suitable feedback taps, an n-bit LFSR cycles through 2ⁿ − 1 states, producing a seemingly random sequence. Because it needs very little logic, it is used for pattern generation in built-in self-test (BIST), CRC calculation, scramblers and similar purposes.
- A. Correct. It is used for pseudo-random and test patterns and CRCs.
- B. It is not used for measuring precise time.
- C. An LFSR is a digital circuit and does not amplify analog signals.