# SNR per bit
aka energy per bit to noise power spectral density ratio
Useful for comparing digital modulation schemes without considering bandwidth.
## General description
A dimensionless ratio of energies commonly expressed in dB.
 directly indicates the power efficiency of the system without regard to modulation type, error correction coding or signal bandwidth (including any use of [spread spectrum](https://en.wikipedia.org/wiki/Spread_spectrum "Spread spectrum")). This also avoids any confusion as to _which_ of several definitions of "bandwidth" to apply to the signal
[^1]
# References
[^1]: https://en.wikipedia.org/wiki/Eb/N0