The Channel from a Space Probe to Earth Has a Bandwidth

Short Answer

The channel from a space probe to earth has a bandwidth $B = 10 ^ { 6 }$ Hz and a channel capacity C = $0.8 \times 10 ^ { 7 } \text { bps }$ .The signal-to-noise ratio $\sigma _ { s } { } ^ { 2 } / \sigma _ { N } { } ^ { 2 }$ equals ______.