where f p {\displaystyle f_{p}} is the pulse frequency (in pulses per second) and B {\displaystyle B} is the bandwidth (in hertz). The quantity 2 B {\displaystyle 2B} later came to be called the Nyquist rate, and transmitting at the limiting pulse rate of 2 B {\displaystyle 2B} pulses per second as signalling at the Nyquist rate. Nyquist published his results in 1928 as part of his paper "Certain topics in Telegraph Transmission Theory".