Magnetic tape coder and decoder

Abstract

The need for the magnetic tape coder and decoder system and the requirements set forth for its operation are discussed. The coder output which is to be recorded serially on one channel of a frequency modulated tape recorder is in the form of four digit, binary-coded-decimal numbers in which the binary bit "0" is represented by a voltage level of +1 volt and the binary bit "1" is represented by +2 volts. The code word nuMbers are generated sequentially from the number 0 to the number 9999. When a code word number is to be sought at a later time in the decoding operation, the output of the tape recorder is connected to the input of the decoder and the tape is then searched. When the decoder senses the code word which is present on the dials of a Digiswitch, a relay is closed in order to perform other desired operations such as the copying of the data at any particular point of the original coded tape onto other tapes. A discussion of the system logic design is presented, followed by a discussion and analysis of the individual circuits, their waveforms, their interconnections, and their interactions with one another.