Describe modulation.

Description should include

• modulator
• demodulator
• modulation: amplitude, frequency, phase
• Silicon Controlled Rectifiers (SCRs)
• Silicon Controlled Switches (SCSs)
• triode alternating current (TRIAC)
• diode alternating current (DIAC). 

Process/Skill Questions:

• How can pulse-width modulation be tested without an oscilloscope?
• How can servomotors be controlled through modulation?
• What is the difference between amplitude modulation and frequency modulation?