Fast Signal and Noise Measurement Technique
Original Publication Date: 1984-Aug-01
Included in the Prior Art Database: 2005-Feb-06
The signal-to-noise ratio (SNR) measurement technique requires only one signal frequency (l MHz) to be written on a track and the overall SNR is thereafter derived from the read-back harmonics. For example, the true signal strength at 3 MHz would be three times the measured third harmonic. The figure shows the measurement setup. The measuring sequences are as follows: Step l: The front-end electronics (or pre-amp) noise floor (see figure). A) With the disk not spinning, connect the head to the pre-amp. B) Using the HP 3585A Spectrum Analyzer, record the noise level (voltage density) at each discrete frequency sample (l MHz, 2MHz,---).