NANOSCALE STANDARD DIGITAL MODULES - Bio-Inspired and Nanoscale Integrated Computing - page 254

TABLE 9 . 9 . Frequency Assignments in the First Method of
Demultiplexer Implementation
Node Sending frequency Receiving frequency

Binary select inputs f adc -

Data input Variable (f i ) f adc

Output i - f i

data sent by the data-input node. Table 9.9 shows the frequency assignments for
the first method of implementing a spin-wave demultiplexer.
The other possible implementation would require the demultiplexing to be
performed in two steps. In the first step, all the output nodes' receiving frequencies
are tuned on a common frequency f adc so that all the nodes receive the analog
value of select-input. All the output nodes compare the select value to their own
index to see which output is selected. In the second step, the selected output node
tunes its frequency on the input node's sending frequency. The data-input node
broadcasts a spin-wave with an amplitude equal to its data, and the selected
output receives and outputs it. Table 9.10 shows the frequency assignments for the
second method of implementing a spin-wave demultiplexer.

9.4. MORE COMPLEX NANOSCALE SPIN-WAVE DIGITAL MODULES

In this section, we demonstrate how to implement more complex modules such as
priority encoders and shifters. We present two implementations for a simple
shifter and show how to extend one to design a spin-wave p-shifter. Next, we show
how to implement a regular and also programmable priority encoder by using
spin-wave switches.

9.4.1. Nanoscale Spin-Wave Shifter
In this section we first present two methods for implementing a simple shifter. In
the first method, we use assigned frequencies for parallel intercommunications
between adjacent nodes. In the second method, we use spin-wave switches to

TABLE 9 . 10 . Frequency Assignments in the Second Method of
Demultiplexer Implementation
Node Sending frequency Receiving frequency

Binary select inputs f adc -

Outputs (step 1) - f adc

Data input f out -

Output i (step 2) - f out