The magnetic matrix recorder (MMR) principle

The working principle of the Magnetic Matrix Recorder is one of hard-axis fall-back. While the relaxation time may be several nanoseconds, the commitment time is a fraction of a nanosecond. The recorder sampling time is thus tens of picoseconds, allowing a gigahertz response at a low resolution, or 100 MHz response at 6-bit (1.6 percent) resolution. A 1 ns rise-and-fall-time pulse was demonstrated in a 10 level matrix recording. The Mated-Film cores in the matrix presently allow expansion to 100 levels (6 1/2 bits) or 1000 levels (10 bits) if calibrated. Presently, a severe limitation exists in time coverage due to the degradation of the analog signal along the bit line. The required low-dispersive Permalloy has only been obtained on a rather thin bit line, making the line resistive and dispersive to the signal. To minimize signal path length, the bit lines are fed in parallel. The number of quantizing levels, resolution, may thus be limited by available signal current. The performance limiting factor is not the Mated-Film core, but the conductor.