using multisim program.

3) Eight people are in eight separate sound-isolated rooms, RO, R1..., R7. Each person is given a microphone for a total of 8 microphones which are all connected to one common speaker through a voice mixer. Each room includes an LED such that when turned ON, the person in that room and only he/she should speak. It is desired to have only one person speak at any given time which should be guaranteed by having exactly one LED to turn ON at any given time. Using the test board, one 74138 Decoder chip and a single 7404 Inverter chip, design and implement the 8 LED controller that can be set to turn ON a single LED at a time. The inputs Ao, A1, A2 must be connected to switches to represent the room number (in binary) of the LED to be turned ON. Input E is used as enable for the contorller. The outputs (Ro Ry) must be connected to 8 LEDs. Connect the circuit to a power supply then complete the logic truth table shown in Table-3A, based on the knowledge that when the output is logic (0), light is ON and when the output is logic (1) the light OFF. Note: Since logic (0) should turn the output LED ON, make sure you properly connect the LED's Anode to VCC (+5V) and the cathode to the output pin. What is the function of this circuit? R A2 Outputs R4 R3 R7 R6 R$ R2 R1 Ro E 0 1 1 1 1 1 1 1 1 Inputs A1 X X 0 0 0 0 0 1 0 1 1 0 1 0 1 1 1 1 0 1 0 1 0 1 0 1 Table-3A