Digital measurement of narrowband noise power

A digital measurement method for narrowband noise power is described and analyzed in the case of flat spectrum Gaussian noise. Noise power is measured by counting the number of times the noise voltage crosses upwards a fixed voltage level. The method should be useful in noise-figure measurements, and by applying it a digital radiometer can be constructed. This digital radiometer has the same theoretical (about 9 percent worse than the best possible radiometer) as conventional radiometers now in use but offers several advantages in comparison with them. A switched digital radiometer is somewhat more sensitive to large gain variations than a normal switched radiometer.