ANACOM 1/1 Module Setup Procedures
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Questions and Answers

What is the primary function of the CERAMIC BANDPASS FILTER block in the procedure?

  • To amplify the audio signal
  • To pass the upper sideband while blocking the lower sideband (correct)
  • To ensure the output signal has constant amplitude
  • To modulate the audio frequency signal

    • Which initial condition does NOT need to be satisfied before powering on the ANACOM 1/1 board?

  • AUDIO INPUT SELECT switch in INT position
  • OUTPUT AMPLIFIER’s GAIN preset in fully clockwise position
  • SPEAKER switch in ON position (correct)
  • MODE switch in SSB position

    • What happens to the waveform at t.p.20 after passing through the CERAMIC BANDPASS FILTER block?

  • It shows random fluctuations in amplitude
  • It changes to a square wave form
  • It becomes distorted by external noise
  • It appears as a good, clean sine wave (correct)

    • What adjustment can be made to vary the modulating frequency of the audio signal?

    <p>Turn the AUDIO OSCILLATOR’s FREQUENCY preset</p> Signup and view all the answers

    What does the output signal at t.p.20 reveal about the performance of the CERAMIC BANDPASS FILTER?

    <p>It confirms the filter is only passing the upper sideband</p> Signup and view all the answers

    What initial position should the BALANCE preset be set to before monitoring outputs?

    <p>Fully clockwise position</p> Signup and view all the answers

    How does changing the modulating frequency affect the amplitude of the signal at the output of the CERAMIC BANDPASS FILTER?

    <p>It results in variation of output signal amplitude</p> Signup and view all the answers

    What is the purpose of examining the waveforms in the BALANCE MODULATOR & BANDPASS FILTER CIRCUIT 1 block?

    <p>To verify that output waveforms match expected patterns</p> Signup and view all the answers

    Which preset position should the AUDIO OSCILLATOR’s AMPLITUDE be in for proper conditions on the ANACOM 1/1 board?

    <p>Fully clockwise position</p> Signup and view all the answers

    What is the required setting for the MODE switch on the ANACOM 1/1 board?

    <p>SSB position</p> Signup and view all the answers

    What should the OUTPUT AMPLIFIER's GAIN preset be set to on the ANACOM 1/1 board?

    <p>Fully counter-clockwise position</p> Signup and view all the answers

    When the AMPLITUDE preset is turned fully counter-clockwise, what happens to the monitored output signal from ANACOM 1/1?

    <p>The amplitude drops to zero</p> Signup and view all the answers

    In order to monitor the I.F. AMPLIFIER 2 output on the ANACOM 1/2 module, what should you adjust?

    <p>TUNING dial</p> Signup and view all the answers

    What must be ensured about the RX INPUT SELECT switch for proper operation?

    <p>It should be in ANT position</p> Signup and view all the answers

    What effect does touching ANACOM 1/1’s antenna have on the SSB waveform at t.p. 13?

    <p>It decreases the amplitude</p> Signup and view all the answers

    What is the correct position for the AGC switch on the ANACOM 1/1 board?

    <p>IN position</p> Signup and view all the answers

    What is the result of adjusting the CARRIER FREQUENCY preset to 450 kHz?

    <p>It allows modulation of the carrier with the audio signal.</p> Signup and view all the answers

    What should be monitored at t.p.52 when varying the frequency of the signal generator?

    <p>The DC voltage corresponding to frequency changes.</p> Signup and view all the answers

    When applying the output from the Foster-Seeley block to the LOW PASS FILTER, what component should be removed?

    <p>The high-frequency ripple component.</p> Signup and view all the answers

    How is the FM signal modulated in this experiment?

    <p>By both the audio input and the noise input.</p> Signup and view all the answers

    What is the amplitude of the sinusoidal output used to test the Foster-Seeley detector?

    <p>1V (p-p) for the initial input.</p> Signup and view all the answers

    What is observed at t.p.14 during the monitoring phase?

    <p>The audio modulating signal.</p> Signup and view all the answers

    What effect does applying a 2 kHz noise signal have on the FM signal?

    <p>It introduces additional amplitude modulation to the FM signal.</p> Signup and view all the answers

    What should the curve represent when plotting DC level against frequency after varying the signal generator's frequency?

    <p>A curve that resembles the expected output pattern.</p> Signup and view all the answers

    What must be adjusted in MODULATOR 2 to achieve equal amplitude of frequency components in the DSK signal?

    <p>GAIN control</p> Signup and view all the answers

    What frequency corresponds to a data bit value of ‘1’ in the FSK signal?

    <p>1.44 MHz</p> Signup and view all the answers

    What effect does the higher incoming frequency have on the output voltage of MODICOM 5/2’s FSK DEMODULATOR?

    <p>It increases the output voltage</p> Signup and view all the answers

    What is the main purpose of the low pass filtering stage in the demodulation process?

    <p>To remove unwanted frequency components</p> Signup and view all the answers

    What adjustment is necessary for the output pulses of COMPARATOR 1 to match the pulse width of MODICOM 5/1’s NRZ(L) output?

    <p>Set the BIAS level</p> Signup and view all the answers

    What should happen after turning on MODICOM 3/1’s SYNC CODE GENERATOR?

    <p>Ensure synchronization of codes between A/D and D/A converters</p> Signup and view all the answers

    When using function generators with MODICOM 3/1, what does the user check at MODICOM 3/2’s analog outputs?

    <p>The inputs are successfully reconstructed</p> Signup and view all the answers

    What is the end result of frequency modulation by MODICOM 5/1’s NRZ(L) output?

    <p>A frequency-modulated carrier signal</p> Signup and view all the answers

    What is the effect of increasing the sampling frequency on the ability to reconstruct the original waveform?

    <p>It allows for better reconstruction of the original waveform.</p> Signup and view all the answers

    How does varying the sampling duty cycle affect the output amplitude of the filter in a practical digital communications system?

    <p>The output amplitude remains independent of the duty cycle.</p> Signup and view all the answers

    What is the primary purpose of the sample/hold circuit in a digital communications system?

    <p>To hold each sampled signal before low-pass filtering.</p> Signup and view all the answers

    When comparing the outputs of the Second Order Low Pass Filter and Fourth Order Low Pass Filter, what factor is being analyzed?

    <p>The amount of distortion in the waveforms.</p> Signup and view all the answers

    At what sampling frequency does the amplitude of the filter output become equal to that of the original analog input?

    <p>When the sampling frequency is at least 32 kHz.</p> Signup and view all the answers

    What happens to the filter output signal as the sampling frequency is changed using the FREQUENCY SELECTOR switch?

    <p>It alters the output waveform significantly.</p> Signup and view all the answers

    What is the significance of using a 50% duty cycle in the sampling process?

    <p>It provides a balanced sampling and holding time.</p> Signup and view all the answers

    What is an expected outcome when displaying the SAMPLE/HOLD OUTPUT on an oscilloscope?

    <p>The output will resemble the original sine wave.</p> Signup and view all the answers

    Study Notes

    ANACOM 1/1 Module Setup and Operation

    • Connect the ANACOM 1/1 module to the power supply properly.
    • Set the following initial board conditions:
      • AUDIO INPUT SELECT switch to INT
      • MODE switch to SSB
      • OUTPUT AMPLIFIER’s GAIN preset fully clockwise
      • SPEAKER switch in OFF position.
    • Power on the ANACOM 1/1 board.
    • Adjust the AUDIO OSCILLATOR block’s AMPLITUDE preset to maximum, and verify output sine wave frequency using an oscilloscope (300Hz to 3.4KHz).
    • Set the BALANCE preset in BALANCE MODULATOR & BANDPASS FILTER CIRCUIT 1 fully clockwise.
    • Monitor output from BALANCE MODULATOR & BANDPASS FILTER CIRCUIT 1 and 2 at specified test points.
    • Observe DSBSC output entering the CERAMIC BANDPASS FILTER, focusing on upper sideband transmission only.

    Monitoring and Signal Examination

    • Verify the output of the CERAMIC BANDPASS FILTER using an oscilloscope; check for clean sine wave.
    • Note any amplitude variation in filter output due to frequency response changes.
    • Ensure all other initial conditions are met for further operations, including proper settings for TX OUTPUT SELECT and AUDIO AMPLIFIER’s VOLUME.
    • Check the Transmitter’s output signal (t.p. 13) for good SSB waveform consistency across AUDIO OSCILLATOR’s FREQUENCY preset adjustments.
    • Confirm zero amplitude output when the AMPLITUDE preset is fully counter-clockwise.

    Transmitter-Receiver Communication

    • Test SSB signal transmission to ANACOM 1/2 Receiver and verify through antenna loading effects.
    • On receiver module, adjust settings to maximize I.F. AMPLIFIER 2 block output.

    Frequency Modulation and Demodulation with Foster-Seeley Detector

    • Connect a signal generator (1V p-p, 400 kHz) to the Foster-Seeley Detector block.
    • Vary signal frequency from 430 kHz to 480 kHz, recording DC voltage at t.p.52 in 5 kHz steps for a frequency-voltage curve.
    • Adjust CARRIER FREQUENCY preset to 450 kHz, modulate the signal from AUDIO OSCILLATOR, and apply it to the Foster-Seeley block.
    • Monitor combined signals to identify sine wave and high-frequency ripple components.
    • Use LOW PASS FILTER/AMPLIFIER to remove ripple and observe the filtered output.

    Noise Impact on System

    • Introduce noise (100 mV p-p, 2 kHz) to observe effects on FM output.
    • Monitor input audio and LOW PASS FILTER output to evaluate ripple presence.
    • Use SAMPLE/HOLD OUTPUT linked to FOURTH ORDER LOW PASS FILTER to analyze original waveform reconstruction.

    Frequency and Duty Cycle Adjustments

    • Vary sampling frequency and duty cycle to examine filter output amplitude consistency.
    • Compare outputs from FIRST and SECOND ORDER LOW PASS FILTERS under varied sampling frequencies for distortion assessment.
    • Primary objective: Perform frequency modulation signal generation and detection using MATLAB Simulink.
    • Adjust GAIN control on MODULATOR 2 to balance frequency components of DSK signal.
    • Analyze the FSK signal and note variations during data changes (0 and 1).
    • Remove unwanted carrier frequencies using low pass filtering and ensure output signal squaring with the correct pulse width adjustment.

    System Functionality Verification

    • Confirm synchronization across components and functionality of the FSK Transmitter-Receiver system.
    • Allow testing of analog inputs and real-time reconstruction at modular outputs.

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    Quiz Team

    Description

    This quiz tests your knowledge on the proper setup and initial conditions required for operating the ANACOM 1/1 module. Key focus areas include power supply connection, switch positions, and settings adjustments for optimal performance. Assess your understanding of the module's configuration steps.

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