In this lab we have the following experiments:‎

Experiment one: Signal Source

The aim of this experiment is to introduce the signal source model and show how ‎its output frequency is controlled by its voltage and the dB scale of attenuation.

Lab work:‎

  • Calibrating of the VCO.
  • Use of external frequency control inputs.
  • Calibrating the attenuator.‎

Experiment two: Tuned Circuit

Th aim of this experiment is to show that the parallel combination of inductance ‎and capacitance forms a "tuned circuit" which resonates at particular frequency. It ‎also aims to show that tuned circuits can be used to respond selectivity to signals ‎of particular frequencies, to show that their selectivity depends on the 'damping ' ‎or energy losses associated with the circuit.‎

Lab work:‎

  • Damped Oscillation.
  • Frequency Response.

Lab Technican:

In this lab we have the following experiments:‎

Experiment one: Signal Source

The aim of this experiment is to introduce the signal source model and show how ‎its output frequency is controlled by its voltage and the dB scale of attenuation

Lab work:‎

  • Calibrating of the VCO.
  • Use of external frequency control inputs.
  • Calibrating the attenuator.‎

Experiment two: Tuned Circuit

Th aim of this experiment is to show that the parallel combination of inductance ‎and capacitance forms a "tuned circuit" which resonates at particular frequency. It ‎also aims to show that tuned circuits can be used to respond selectivity to signals ‎of particular frequencies, to show that their selectivity depends on the 'damping ' ‎or energy losses associated with the circuit.‎

Lab work:‎

  • Damped Oscillation.
  • Frequency Response.

Experiment three: Amplitude Modulation

The aim of this experiment is to see that amplitude modulation is causing the ‎amplitude of the carrier to vary in accordance with the modulating signal, to see ‎that AM is a multiplicative process which produces side frequencies. This ‎experiment can also show that the original signal can be recovered by further ‎modulation process.‎

Lab work:‎

  • Multiplying action of the modulator.‎
  • AM modulation using Balanced modulator.‎
  • AM demodulation using Balanced modulator.‎
  • SC AM modulation.‎
  • Square law Detection. ‎

Experiment four: AM Detection and Demodulation

This experiment shows that a diode may be used for detecting a normal ‎amplitude modulated signal and that to avoid distortion of the signal, the signal ‎level and time constants associated with the circuit must be chosen carefully. It ‎also shows a dc component in the detected signal, dependent on the carrier ‎amplitude, can be used for automatic gain control AGC.‎

Lab work:‎

  • Diode Detector.
  • Automatic Gain Control (AGC).

Experiment five: Single –Sideband Transmission

This experiment helps students understand the term single-sideband ‎transmission and demonstrates a method of producing and receiving a single-‎sideband transmission. It also shows the importance of synchronising the carrier ‎signal used for modulation processes at transmitter and receiver. ‎

Lab work :‎

  • SSB transmitter.
  • The Local Oscillator.
  • SSB Receiver.

Experiment six: FM Modulation and Demodulation

This experiment aims to show that a carrier may be modulated by changing its ‎frequency in accordance with the signal,a frequency-modulated signal has many ‎side bands, dependent on the amplitude as well as the frequency of the ‎signal, FM provides improved immunity from interfering signals, with increasing ‎bandwidth compared with AM. It also demonstrates how to adjust and use FM ‎detector .‎

Lab work :‎

  1. Setting up a FM signal.
  2. Display of the Side Frequencies.
  3. FM detection (using the phase shift Detector)‎.

Experiment seven: Sampling

Experiment seven is used to demonstrate what sampling is and what sample and ‎hold is. It demonstrates the sampling theorem and aliasing frequencies and helps ‎understand the effect of filters in eliminating aliasing, Time Division Multiplexing ‎and Pulse Amplitude modulation and Pulse width modulation .  ‎

Lab work:

  • Sample and Hold
  • Aliasing ‎
  • TDM multiplexing

Experiment eight: Delta and Sigma Delta Modulation

This experiment helps explain the  process of delta modulation and sigma delta ‎modulation. It shows that each of these systems is a simple form of digital ‎communication. The experiment also helps students to understand that digital ‎communication has to distort the signal to some extent, in order to quantise it, ‎but that this enables subsequent distortion noise introduced by the channel to be ‎largely rejected

Lab work‏ :‏

  • Delta modulation.
  • Sigma-Delta Modulation.

Experiment nine: Pulse Code Modulation (PCM)‎

Experiment nine demonstrates how to generate Pulse Amplitude Modulation ‎‎(PAM) and to demodulate (PAM), as well as how to understand sampling theorem ‎and "sample and hold" concept, the pulse code modulation concept and the need ‎of synchronisation in PCM.‎

Lab work :‎

  • PAM(Generation of PAM, Demodulation of PAM).‎
  • Sample and Hold ( Basic operation, Demodulation of PAM using SH).‎
  • PCM( PCM and serial transmission, signal transmission using 4-bit PCM, voice ‎transmission using 8-bit PCM).‎

Experiment ten: Data Formats and Noise in Digital  systems

Experiment ten demonstrates that a binary coded waveform can be represented ‎by a number of different data formats using either unipolar or bipolar signals and ‎that the data format is selected to match the characteristic of the channel ‎available for transmission. It also aims to demonstrate that there are three forms ‎of additive noise which can be present in a communication system  ‎

Lab work :‎

  • Examination of different data formats.
  • Extraction of clock signals.
  • Noise in digital systems.‎

Experiment eleven: Amplitude Shift Keying (ASK)

Experiment eleven is demonstrated through an on-off ASK system the carrier wave is constant and carries no information. The modulation by ‎a bipolar data signal produces a suppressed carrier system with a significant improvement in efficiency. A suppressed carrier system requires a ‎locally re-generated carrier signal at the receiver.  ‎

Lab work:

  • On-Off ASK.
  • Suppressed carrier ASK.

Manual