What material is used in filters to assist in the rejection of unwanted signals?

What material is used in filters to assist in the rejection of unwanted signals?

• A. Crystal-controlled Oscillator
• B. Use of Crystals
• C. High-pass
• D. Filtering

Answer: (B)

Crystal filters use quartz crystals as the resonant element. The piezoelectric nature of quartz lets it resonate at a very precise, stable frequency with a high Q, producing a narrow passband and steep rejection of signals outside that band—the trait that helps reject unwanted signals. The crystal-controlled oscillator uses a crystal for frequency stabilization, not filtering; a high-pass is a filter type, and filtering describes the process rather than the material.

Crystal filters use quartz crystals as the resonant element. The piezoelectric nature of quartz lets it resonate at a very precise, stable frequency with a high Q, producing a narrow passband and steep rejection of signals outside that band—the trait that helps reject unwanted signals. The crystal-controlled oscillator uses a crystal for frequency stabilization, not filtering; a high-pass is a filter type, and filtering describes the process rather than the material.