PC1: Modulation Flashcards
What are the RF Signal classifications?
- Analog Signals (Continuous)
- Digital Signals (Discrete)
Modulation is the process of what?
Superimposing a low frequency signal onto a higher frequency signal
Fourier Transfer is used to what?
Convert a signal between the frequency and time domains
What is Pulse Code Modulation (PCM) used for?
Convert analog signals to digital signals
What are the 3 steps to Pulse Code Modulation (PCM)?
- Sampling - reading filtered signals at discrete time intervals
- Quantizing - assigning values
- Encoding - changing to binary
Define:
Constellation Diagrams
A graphical representation of digital modulation techniques
Ex. Phase Shift Keying (PSK) and Quadrature Amplitude Modulation (QAM)
What are the Modulations?
- Amplitude Modulation (AM)
- Frequency Modulation (FM)
- Phase Modulation (PM)
What does Amplitude Modulation (AM) do?
Modulate amplitude
It is the oldest and easiest form of modulation - ex. talk radios
What does Frequency Modulation (FM) do?
Modulate frequency
Popular because it doesn’t require complex hardware. Think of all the radio stations we have.
What is Digital Modulation also known as?
Shift Keying
What are the Digital Modulations?
- Amplitude Shift Keying (ASK)
- Frequency Shift Keying (FSK)
- Phase Shift Keying (PSK)
- Quadrature Amplitude Modulation (QAM)
What is Quadrature Amplitude Modulation (QAM) a combination of?
Amplitude and phase modulation
What is the digital equivalent of PM?
Phase Shift Keying (PSK)
What is the digital equivalent of FM?
Frequency Shift Keying (FSK)
What is the digital equivalent of AM?
Amplitude Shift Keying (ASK)
What is the base of binary code?
Two
This means that binary information can have only two states 0 and 1
Digital Signals are represented by what kind of waves?
Square waves
Analog Signals are represented by what kind of wave?
A sine wave
How do analog signals transmit data?
In the form of a wave
How do digital signals carry data?
In the form of bits
