Simple two way intercom

This intercom circuit is based on LM386 low voltage audio amplifier. It uses 8 ohm speaker works as microphone and speaker at the same time. 10k potentiometer is used to control the volume. As a double pole double throw switch is used in this circuit it reverses the speaker’s position and makes one as loudspeaker and another as microphone.

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Architecture of a Typical Microcontroller

Microcontrollers are the building blocks of any digital signal processing system. In layman’s terms, they can be described as miniature computers that are present on chips. They consume very little amount of power and are self sufficient. They are similar to microprocessors but contain some additional elements such as read only memory in the form of EEPROM (Electrical Programmable Read Only Memory) and a read write memory that usually utilises flash technology. Another difference between microcontrollers and microprocessors is the clock speed. Microcontrollers usually operate at low clock speeds. Low clock speeds are adopted as they are suitable for the operations that are usually performed using microcontrollers. Also, this ensures that they consume less power.

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About Digital Signal Processing

Today, signals i.e. quantities that fluctuate over a period of time with usually with high frequency have acquired a great amount of importance and are being used in many fields especially in communication. Digital signal processing involves conversion of digital data into signals thus, making its transfer easier and subsequently converting these signals back into the original form. A signal has many characteristics or domains such as time domain, spatial domain, frequency, wavelet domain etc. Any one among these can be used to process a respective signal. From among these, the engineer usually selects the one that best represents the characteristics of the signal concerned or in other words, the one from which data can be obtained easily. In order to ascertain the required characteristic, the engineer may try out many among these properties. The use of signals has gone up especially with the use of computers. Computers are capable of analyzing and processing only digital (discrete) data and cannot handle analogue (continuous) data. Thus, conversion of the signal from analogue to the digital form becomes necessary. In order that the digital signal is exactly similar to the analogue signal that it has been obtained from, some mathematical techniques such…

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