What is meant by direct digital conversion as applied to software defined radios?

  1. Software is converted from source code to object code during operation of the receiver
  2. Incoming RF is converted to a control voltage for a voltage controlled oscillator
  3. Incoming RF is digitized by an analog-to-digital converter without being mixed with a local oscillator signal
  4. A switching mixer is used to generate I and Q signals directly from the RF input


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

  1. An adaptive filter
  2. A crystal-lattice filter
  3. A Hilbert-transform filter
  4. A phase-inverting filter


What type of digital signal processing filter is used to generate an SSB signal?

  1. An adaptive filter
  2. A notch filter
  3. A Hilbert-transform filter
  4. An elliptical filter


What is a common method of generating an SSB signal using digital signal processing?

  1. Mixing products are converted to voltages and subtracted by adder circuits
  2. A frequency synthesizer removes the unwanted sidebands
  3. Emulation of quartz crystal filter characteristics
  4. Combine signals with a quadrature phase relationship


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

  1. At half the rate of the highest frequency component of the signal
  2. At twice the rate of the highest frequency component of the signal
  3. At the same rate as the highest frequency component of the signal
  4. At four times the rate of the highest frequency component of the signal


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?

  1. 4 bits
  2. 6 bits
  3. 8 bits
  4. 10 bits


What function can a Fast Fourier Transform perform?

  1. Converting analog signals to digital form
  2. Converting digital signals to analog form
  3. Converting digital signals from the time domain to the frequency domain
  4. Converting 8-bit data to 16 bit data


What is the function of decimation with regard to digital filters?

  1. Converting data to binary code decimal form
  2. Reducing the effective sample rate by removing samples
  3. Attenuating the signal
  4. Removing unnecessary significant digits


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

  1. It removes high-frequency signal components which would otherwise be reproduced as lower frequency components
  2. It peaks the response of the decimator, improving bandwidth
  3. It removes low frequency signal components to eliminate the need for DC restoration
  4. It notches out the sampling frequency to avoid sampling errors


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

  1. Sample rate
  2. Sample width in bits
  3. Sample clock phase noise
  4. Processor latency


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

  1. Sample clock phase noise
  2. Reference voltage level and sample width in bits
  3. Data storage transfer rate
  4. Missing codes and jitter


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

  1. Fast Fourier Transform
  2. Decimation
  3. Signal conditioning
  4. Quadrature mixing


What is the function of taps in a digital signal processing filter?

  1. To reduce excess signal pressure levels
  2. Provide access for debugging software
  3. Select the point at which baseband signals are generated
  4. Provide incremental signal delays for filter algorithms


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

  1. Higher data rate
  2. More taps
  3. Complex phasor representations
  4. Double-precision math routines


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

  1. FIR filters delay all frequency components of the signal by the same amount
  2. FIR filters are easier to implement for a given set of passband rolloff requirements
  3. FIR filters can respond faster to impulses
  4. All of these choices are correct


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

  1. Change the gain by a factor of 3/4
  2. Multiply each sample value by a factor of 3/4
  3. Add 3 to each input value and subtract 4 from each output value
  4. Interpolate by a factor of three, then decimate by a factor of four


What do the letters I and Q in I/Q Modulation represent?

  1. Inactive and Quiescent
  2. Instantaneous and Quasi-stable
  3. Instantaneous and Quenched
  4. In-phase and Quadrature