Day 1: RF Equipment Flashcards by Gray Nguyen

Equipment in a system that supports and allows the transmission of a signal

Transmit (Tx)

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Takes digital information and adapts it to propagate through free space

Transmit (Tx)

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Equipment in a system that supports and allows the reception of a signal

Receive (Rx)

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Usually, takes in analog information and adapts it for delivery for users

Receive (Rx)

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Frequencies used to transmit signals over a distance

Radio Frequency (RF)

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Can be in several bands (UHF, L, S, etc…)

Radio Frequency (RF)

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Can utilize characteristics of different bands to achieve different goals

Radio Frequency (RF)

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Low frequencies (UHF and lower) travel great distances more reliably but sacrifice data rate

Radio Frequency (RF)

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Medium frequencies (L, S, C, and X) interact with the environment (diffract, reflect) and can be manipulated to reach mobile or challenging RXers, and have middling data rates

Radio Frequency (RF)

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Higher frequencies (Ku and above) gradually can support higher and higher data rates but lose power more rapidly and are susceptible to interference

Radio Frequency (RF)

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Frequencies used to standardize a transmission system

Intermediate Frequency (IF)

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Can be in certain bands (L Band, 70/140 MHz)

Intermediate Frequency (IF)

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Used to reduce cost and improve efficiency of a system

Intermediate Frequency (IF)

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All devices can talk without the need for additional converters

Intermediate Frequency (IF)

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Steps in Signal Flow

Baseband Signals
MUX
MODEM - VSG
Converter(s) - U/C, D/C
Amp - HPA, LNA
Antenna - Transmitter, Receiver
TTF

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Any user original signal in its original format - i.e. prior to multiplexing and modulation

Baseband Signals

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Combines baseband signals into a single data stream

Multiplexer

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Can use TDM, FDM, or CDM multiplexing formats

Multiplexer

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Used to generate signals or modulate existing signals

Modulator

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Used to strip off modulation and FEC to reveal data

Demodulator

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Modifies Carrier Wave (CW) to represent data

MODEM

Modulator

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Promotes flexibility in signal characeristics

MODEM

Modulator

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Adds FEC (computational gain)

MODEM

Modulator

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Digital to analog conversion

MODEM

Modulator

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Must match received signal modulation for lock | MODEM

Demodulator

Understands Mod scheme | MODEM

Demodulator

Recognizes and strips off FEC | MODEM

Demodulator

Can be separate from Modulator | MODEM

Demodulator

Analog to digital conversion | MODEM

Demodulator

Sophisticated radio

Vector Signal Generator (VSG)

Produces many signals of varying types/forms

Vector Signal Generator (VSG)

Highly customizable signals (shape RF to desired "form")

Vector Signal Generator (VSG)

Can emulate industry standards

Vector Signal Generator (VSG)

Designed for testing

Vector Signal Generator (VSG)

No actual data sent, modulates pseudo random noise over a carrier

Vector Signal Generator (VSG)

No FEC

Vector Signal Generator (VSG)

Uses Symbol Per Second

Vector Signal Generator (VSG)

* Non-modulated and simplest waveform * A single frequency | VSG Basic Signal Generation Functions

Continuous Waveform (CW)

Modulates noise, no real data, signal takes the form of various modulation schemes | VSG Basic Signal Generation Functions

Modulated Waveform

CW repeats moving back and forth within a given frequency range | VSG Basic Signal Generation Functions

Sweep

CW pulses on and off at a specific frequency & time interval, or across multiple frequencies (hopping) | VSG Basic Signal Generation Functions

Pulsed

The process of **mixing 2 frequencies together** to achieve a desired output | Converters

Heterodyning

Takes an input frequency and a local oscillator and creates 4 frequencies, and filters for a desired result: * Input * LO * Input + LO * Input - LO | Converters

Heterodyning

IF to RF (low frequency to high frequency) | Converters

Upconverter

Adds active gain (higher frequency = more power) | Converters

Upconverter

Allows for **flexibility in bands** | Converters

Upconverter

RF to IF (high frequency to low frequency) | Converters

Downcoverters

Less attentuation travelling through cables | Converters

Downcoverters

Low Noise Block Downconverters (LNBs) combine what? | Converters

* down conversion * low-noise amplification

The High Power Amplifier (HPA) adds what kind of gain to overcome Free Space Loss (FSL)? | Amplifiers

Active

Increases chances of data transmission | Amplifiers

High Power Amplifier (HPA)

Raises amplitude of received signals after Free Space Loss (FSL) | Amplifiers

Low-Noise Amplifier

The Low-Noise Amplifier filters out what? | Amplifiers

Out of Band Noise

Antennas add what kind of gain? | Antennas

Passive

Directional | Antennas

Transmit

Greatest factor in success/failure | Antennas

Transmit

Focuses signal on feedhorn | Antennas

Receive

Optimized by RF band | Antennas

Receive

The Transponder Translation Factor (or Frequency) (TTF) is the ratio of what?

Downlink frequency to uplink frequency

What does the Transponder Translation Factor (or Frequency) (TTF) do to polarity?

Flips it to the opposite for downlink

What is a "Spec-A?"

* Visual Representation of the EMS (Frequency Domain) * Spectrograph (primary trace) * Spectrogram (waterfall plot)

What are the 2 mission functions of a Spec-A?

* Signal Characterization * Signal Monitoring

Allows tuning to specific center frequency (think RF address) | Basic Sectrum Analyzer Functions

Center Frequency

Selects frequencies displayed on x-axis (think zoom) | Basic Sectrum Analyzer Functions

Span

Sets the amplitude reference (top line of display) | Basic Sectrum Analyzer Functions

Reference Level

Like Span, but for the Y-axis (based on Ref Level) | Basic Sectrum Analyzer Functions

Scales per Division (Scal/Div)

Applies a filter to the frequencies within a span | Basic Sectrum Analyzer Functions

Resolution Bandwidth (RBW) ## Footnote Higher RBW makes smoother signals and lower RBW makes sharper signals

Applies a filter to the sampled amplitude seen on frequencies within a span | Basic Sectrum Analyzer Functions

Video Bandwidth (VBW) ## Footnote Higher VBW creates more noise on the display while lower VBW removes varation

The time it takes for the display to refresh; dependent on setttings and current functions | Basic Sectrum Analyzer Functions

Sweep

Tools used to make specific measurements or perform specific functions | Basic Sectrum Analyzer Functions

Marker/Trace/Measure

What are some spectrum analyzer best practices?

* Center your display * Fill your display * Start with a 100:1 ratio of RBW and VBW