Answer:

The Analog to Digital Converter (ADC) is used at the transmitter in digital data communication.

Explanation:

In digital data communication, analog signals need to be converted into digital signals before transmission. This conversion is done using an Analog to Digital Converter (ADC). The ADC takes in an analog signal and converts it into a digital representation that can be easily transmitted and processed by digital systems.

Role of ADC at the Transmitter:

The ADC plays a crucial role at the transmitter end of a digital data communication system. Here's how it works:

1. Sampling: The ADC samples the analog signal at regular intervals. This involves measuring the amplitude of the analog signal at specific time intervals. The sampling rate determines how often the signal is sampled.

2. Quantization: After sampling, the ADC quantizes the sampled analog signal. Quantization involves dividing the range of amplitudes into discrete levels or steps. Each level represents a specific digital value. The number of levels is determined by the resolution of the ADC.

3. Encoding: Once the analog signal is quantized, the ADC encodes the digital values into binary code. Each quantized level is represented by a digital code, typically in the form of binary numbers.

4. Data Transmission: The digital signal generated by the ADC is then transmitted over the communication channel. It can be transmitted using various modulation techniques such as amplitude modulation (AM), frequency modulation (FM), or phase modulation (PM).

5. Error Correction: At the receiver end, the digital signal may undergo noise and distortion during transmission. To overcome this, error correction techniques are employed to ensure the accurate reception of the digital signal.

Conclusion:

The ADC is used at the transmitter in digital data communication to convert analog signals into digital signals. This conversion allows for efficient transmission and processing of data in digital systems.