Purchase Solution

Electrical Signal Feedback

Not what you're looking for?

Ask Custom Question

Please answer the following questions.

(a) It is found that if a microphone is brought into the proximity of a loudspeaker on a public address (P.A.) system, the system will `howl'. Carefully explain, making reference to feedback theory, why this is so.
(b) Suggest two actions that could be adopted to remedy the howling.
(c) Represent the howling system by a block diagram.
(d) Measurements show that for a particular arrangement of the equipment and at a particular amplifier setting, the system will howl if 1% of the output power is fed back to the microphone. Estimate the power gain of the P.A. amplifier in decibels.
(e) Analysis shows that the frequency at which the system howls; is 16 kHz and it is proposed to use a filter to attenuate all frequencies above 14 kHz. This is to be done using a simple RC filter. If the resistor in the filter has a value of 10 k, calculate a suitable value for the capacitor.

Purchase this Solution
Solution Summary

This posting contains the solution to the given problems.

Purchase this Solution
Free BrainMass Quizzes
Air Pollution Control - Environmental Science

Working principle of ESP

Architectural History

This quiz is intended to test the basics of History of Architecture- foundation for all architectural courses.

View More Free Quizzes
Related BrainMass Solutions

  • Neurotransmitters Process

    Depolarization occurs when a large electrical signal called the threshold is reached. The signal is then sent quickly to the axon terminal where neurotransmission begins and conduction ends.

  • The Neuron and Its Process

    The receiving neuron then converts the chemical signal back into an electrical signal and passes it on to another neuron. It is a continual process.

  • Integumentary and Nervous systems

    Myelin insulates the neuron (like a rubber covering around an electrical wire), so the signal stays inside and is able to move down the axon without dissipating.

  • Op-Amp

    , the lower the gain and thus the higher the attenuation of the signal.

  • Armstrong oscillator with secondary winding's

    • Capacitor then AC couples the feedback signal to the base of the BJT preventing any DC signals from the feedback circuit and supply entering the base of Q2, then in the process preventing disruption of the DC biasing of Q2.

  • Armstrong Oscillator and Feedback Mechanisms Resulting

    It also provides a degree of electrical isolation for the main circuit from the output.

  • the AP is an all-or-none phenomenon

    What makes this phenomenon so interesting is that it is a great example of a positive feedback mechanism.

  • Measurement of Physiology - Respiration Signal

    The resulting signal is contaminated by electrical noise from the mains at 50 Hz with a similar amplitude to the respiration signal. Sketch what the contaminated signal might look like. The signal is then sampled into a computer.

  • Multiple electrical signal, level, noise calcualtions

    Multiple electrical signal type questions, calculations of amplifier levels, noise, SNR, resolution, ADC, NEXT and FEXT crosstalk voltages.

View More Related Solutions