Final answer:
To build a 4-bit LFSR on Tinkercad, use flip-flops and XOR gates. Determine the count sequence by shifting the bits. Choose a primitive polynomial.
Step-by-step explanation:
A 4-bit Linear Feedback Shift Register (LFSR) is a circuit that generates a sequence of binary numbers based on a given polynomial. To build a 4-bit LFSR on Tinkercad, you can use flip-flops to represent the individual bits, and XOR gates to implement the feedback mechanism.
For example, you can connect the output of the first flip-flop to the input of the fourth flip-flop through an XOR gate. The XOR gate takes in the feedback bit and another bit as inputs, and outputs the result. This result is then fed back to the fourth flip-flop, completing the feedback loop.
To determine the count sequence of the LFSR, you can start with an initial state, and then shift the values of each bit to the right. The rightmost bit is replaced with the result of the XOR gate, and the other bits are shifted to the right. This process is repeated, and the sequence of the values taken by the bits forms the count sequence of the LFSR.
To ensure the generating polynomial is primitive, you need to select a polynomial that meets certain criteria. A polynomial is primitive if its corresponding LFSR generates all possible non-zero combinations of bits, except for an all-zero state. Primitive polynomials for 4-bit LFSRs include x^4 + x + 1 and x^4 + x^3 + 1.