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Extra Class Exam Question Pool

effective 7/01/2016 thru 6/29/2020

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2016-E7F: DSP filtering and other operations; Software Defined Radio Fundamentals; DSP modulation and demodulation

2016-E7F01: What is meant by direct digital conversion as applied to software defined radios?

Incoming RF is digitized by an analog-to-digital converter without being mixed with a local oscillator signal

Software is converted from source code to object code during operation of the receiver

Incoming RF is converted to a control voltage for a voltage controlled oscillator

A switching mixer is used to generate I and Q signals directly from the RF input

2016-E7F02: What kind of digital signal processing audio filter is used to remove unwanted noise from a received SSB signal?

An adaptive filter

A crystal-lattice filter

A Hilbert-transform filter

A phase-inverting filter

2016-E7F03: What type of digital signal processing filter is used to generate an SSB signal?

A Hilbert-transform filter

An adaptive filter

A notch filter

An elliptical filter

2016-E7F04: What is a common method of generating an SSB signal using digital signal processing?

Combine signals with a quadrature phase relationship

Mixing products are converted to voltages and subtracted by adder circuits

A frequency synthesizer removes the unwanted sidebands

Emulation of quartz crystal filter characteristics

2016-E7F05: How frequently must an analog signal be sampled by an analog-to-digital converter so that the signal can be accurately reproduced?

At twice the rate of the highest frequency component of the signal

At half the rate of the highest frequency component of the signal

At the same rate as the highest frequency component of the signal

At four times the rate of the highest frequency component of the signal

2016-E7F06: What is the minimum number of bits required for an analog-to-digital converter to sample a signal with a range of 1 volt at a resolution of 1 millivolt?

10 bits

4 bits

6 bits

8 bits

2016-E7F07: What function can a Fast Fourier Transform perform?

Converting digital signals from the time domain to the frequency domain

Converting analog signals to digital form

Converting digital signals to analog form

Converting 8-bit data to 16 bit data

2016-E7F08: What is the function of decimation with regard to digital filters?

Reducing the effective sample rate by removing samples

Converting data to binary code decimal form

Attenuating the signal

Removing unnecessary significant digits

2016-E7F09: Why is an anti-aliasing digital filter required in a digital decimator?

It removes high-frequency signal components which would otherwise be reproduced as lower frequency components

It peaks the response of the decimator, improving bandwidth

It removes low frequency signal components to eliminate the need for DC restoration

It notches out the sampling frequency to avoid sampling errors

2016-E7F10: What aspect of receiver analog-to-digital conversion determines the maximum receive bandwidth of a Direct Digital Conversion SDR?

Sample rate

Sample width in bits

Sample clock phase noise

Processor latency

2016-E7F11: What sets the minimum detectable signal level for an SDR in the absence of atmospheric or thermal noise?

Reference voltage level and sample width in bits

Sample clock phase noise

Data storage transfer rate

Missing codes and jitter

2016-E7F12: What digital process is applied to I and Q signals in order to recover the baseband modulation information?

Fast Fourier Transform


Signal conditioning

Quadrature mixing

2016-E7F13: What is the function of taps in a digital signal processing filter?

Provide incremental signal delays for filter algorithms

To reduce excess signal pressure levels

Provide access for debugging software

Select the point at which baseband signals are generated

2016-E7F14: Which of the following would allow a digital signal processing filter to create a sharper filter response?

More taps

Higher data rate

Complex phasor representations

Double-precision math routines

2016-E7F15: Which of the following is an advantage of a Finite Impulse Response (FIR) filter vs an Infinite Impulse Response (IIR) digital filter?

FIR filters delay all frequency components of the signal by the same amount

FIR filters are easier to implement for a given set of passband rolloff requirements

FIR filters can respond faster to impulses

All of these choices are correct

2016-E7F16: How might the sampling rate of an existing digital signal be adjusted by a factor of 3/4?

Interpolate by a factor of three, then decimate by a factor of four

Change the gain by a factor of 3/4

Multiply each sample value by a factor of 3/4

Add 3 to each input value and subtract 4 from each output value

2016-E7F17: What do the letters I and Q in I/Q Modulation represent?

In-phase and Quadrature

Inactive and Quiescent

Instantaneous and Quasi-stable

Instantaneous and Quenched

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2016-E7E: Modulation and demodulation: reactance, phase and balanced modulators; detectors; mixer stages
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2016-E7G: Active filters and op-amp circuits: active audio filters; characteristics; basic circuit design; operational amplifiers
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