Detector recognising special characters in data signals - uses recursive addressing from rough RAM and fine PROM memories

摘要

The detector has RAM with a word storage cell having m bit storage cells for each character address (F) and addressed by it. An input search address (E) with m bits is fed via the inputs to the RAM during each bit of the data signal (A). An output search address (C) of m bits appears at the output of the RAM during each bit of the data signal. The data signal, the bit addresses and the output search addresses are used to address a programmable read only memory PROM). The PROM delivers finer search addresses (D) which are then used as input search addresses (E) to the RAM.