What are the two most-used PCS (Personal...

🔍 Key Concepts

• PCS (Personal Communications Systems) are digital cellular systems that need a way to let many users share the same frequencies without interfering • Common multiple-access / coding methods to separate calls include time, frequency, or code separation • Some options in the choices are modulation schemes (how you put data on a carrier), while others are access/coding techniques (how users are separated)

💭 Think About

• Look at each choice and ask: is this mainly a way to share a channel among many users, or mainly a way to modulate a single user’s signal? • Which pair is most directly associated with digital cellular / PCS standards used worldwide? • Which options are familiar as names of whole cellular technologies, not just signal waveforms?

✅ Before You Answer

• Identify which options are multiple-access / coding methods (for many users) vs. which are primarily modulation methods (for one signal • Recall which abbreviations are widely known as cellular system standards used by carriers (especially 2G/3G era PCS bands) • Eliminate any options that are obviously nonsense labels or generic analog concepts not specific to PCS coding

What are the two most-used PCS (Personal Communications Systems) coding techniques used to separate different calls?

QPSK and QAM.

CDMA and GSM .

ABCD and SYZ.

AM and Frequency Hopping.

🔍 Key Concepts

💭 Think About

✅ Before You Answer