Which circuit takes an input signal with a frequency and outputs a signal with a lower frequency?

Which circuit takes an input signal with a frequency and outputs a signal with a lower frequency?

• A. Oscillator
• B. Frequency Division/Divider
• C. Amplifier
• D. Modulator

Answer: (B)

Reducing the input frequency is done by a frequency divider. A divider counts input cycles and outputs a signal only every N input pulses, so the output frequency is the input frequency divided by N. In digital circuits this is typically built with flip-flops or counters; one simple stage divides by 2 by toggling the output on every clock edge, and chaining stages can divide by larger integers to produce slower timing references or slower data rates. An oscillator, on the other hand, generates a signal at a chosen frequency independently of an input; it doesn’t reduce an external signal’s frequency. An amplifier changes amplitude but leaves the frequency generally unchanged. A modulator combines signals to produce new frequencies (through mixing or shifting), which can create higher or different frequency components rather than simply lowering the input frequency.

Reducing the input frequency is done by a frequency divider. A divider counts input cycles and outputs a signal only every N input pulses, so the output frequency is the input frequency divided by N. In digital circuits this is typically built with flip-flops or counters; one simple stage divides by 2 by toggling the output on every clock edge, and chaining stages can divide by larger integers to produce slower timing references or slower data rates.

An oscillator, on the other hand, generates a signal at a chosen frequency independently of an input; it doesn’t reduce an external signal’s frequency. An amplifier changes amplitude but leaves the frequency generally unchanged. A modulator combines signals to produce new frequencies (through mixing or shifting), which can create higher or different frequency components rather than simply lowering the input frequency.