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This just means that ROM can be used as logic if you think of the address as an input and the data as the output. This implies parallel addressing and parallel output (rather than serial) which probably is what the PLA structure is refering to. Whatever data you store in the ROM becomes the logic output based on the address, and the address is selected via the inputs.
This just means that ROM can be used as logic if you think of the address as an input and the data as the output. This implies parallel addressing and parallel output (rather than serial) which probably is what the PLA structure is refering to. Whatever data you store in the ROM becomes the logic output based on the address, and the address is selected via the inputs.
But how can one implement combinational circuits like **broken link removed** or **broken link removed** using a ROM? Is the text saying that PLA is also a kind of ROM which is used to implement logic?
Could you please help me with these queries too? Thanks.
Most ROMs would have more address inputs and more data outputs than these simple logic circuits. But extra inputs can be tied either high or low, and you can ignore outputs you don't need. Then simply program the ROM with the data that corresponds with the truth table for the logic circuit.
I know you are familial with the Euler relations between sin/cos and the complex exponential functions. A similar set of relations exist for the hyperbolic trig functions and they can be related to ordinary exponential functions.
That looks correct. It's not really that amazing that I can suggest the approach without doing it. Often the form of the identity makes the method clear even without solving it. Of course, I had to assume that the identity was true to have confidence that what I suggested was correct. But, it's a reasonable assumption given that it is in a book. If there had been a typo in the book, ... maybe I wouldn't look so smart right now?
But, let me do it now to show how my mind saw the solution. Often these identities look more complicated than they really are. It's just a matter of getting to the essential problem and being familiar with a few relations.
Watch how we can simplify this using x=Vbe1/Vt and y=Vbe2/Vt and some forethought in deciding what to multiply by (or factor out of) in the numerator and denominator.
Start with [latex] \frac{e^x-e^y}{e^x+e^y}[/latex]
Now multiply this expression by [latex] \frac{\exp{\frac{-x-y}{2}}}{\exp{\frac{-x-y}{2}}} =1[/latex]
This gives [latex] \frac{\exp{\frac{-x-y}{2}}}{\exp{\frac{-x-y}{2}}}\cdot\frac{e^x-e^y}{e^x+e^y}=\frac{\exp{\frac{x-y}{2}}-\exp{\frac{-x+y}{2}}}{\exp{\frac{x-y}{2}}+\exp{\frac{-x+y}{2}}}=\tanh \frac{x-y}{2}[/latex]
But how can one implement combinational circuits like **broken link removed** or **broken link removed** using a ROM? Is the text saying that PLA is also a kind of ROM which is used to implement logic?
Could you please help me with these queries too? Thanks.
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