Quarter-half cycle coding for rotating magnetic memory system

Claim 1

In a rotary magnetic memory system Including an input terminal to which binary information pulses are presented in form of bivalued bits at a particular rate corresponding to a particular bit rate frequency and having means for recording the encoded information pulses in sequential bit frames, one bit frame, and having means for recovering the recorded and encoded information pulses, the improved method for encoding the bits for recording including the steps of: converting each input binary information pulse of a first binary state into a half-cycle pulse of a selected frequency corresponding to half the bit rate frequency of the binary information to be recorded, the half-cycle cycle pulse to be recorded to extend over the entire length of a bit frame; converting each input binary information pulse of the second binary state into a quarter-cycle pulse of one-half said selected frequency, the quarter-cycle pulse to be recorded to extend over the entire length of a bit frame.

Claim 11

The method of recording bivalued digital data along a track and in sequential bit frames, one frame per bit, each bit frame having a trailing boundary and a leading boundary coinciding with the trailing boundary of the respectively immediately preceding frame, the carrier being in one or the other of two different states of energization along the track, there being transition zones between areas of oppositely different states, comprising the steps of: providing a transition on the trailing boundary of a bit frame for a bit of a first one of the two values to be recorded in the bit frame, only if the leading boundary of the bit frame has not been provided with a transition; and providing a transition on the trailing boundary of a bit frame for a bit of the other one of the two values to be recorded in the bit frame, only if the leading boundary of the frame has been provided with a transition, while providing a midframe transition, only if the leading boundary of the frame has not been provided with a transition.

Claim 12

The method of recording bivalued digital data along a track and in sequential bit frames, one frame per bit, each bit frame having a trailing boundary and a leading boundary coinciding with the trailing boundary of the respectively immediately preceding frame, the carrier being in one or the other of two different states of energization along the track, there being transition zones between areas of oppositely different states, comprising the steps of: providing a transition on the trailing boundary of a bit frame for a bit of a first one of the two values to be recorded in the bit frame, only if the leading boundary of the bit frame has not been provided with a transition; and providing a transition on the trailing boundary of a bit frame for a bit of the other one of the two values to be recorded in the bit frame, only if the leading boundary of the frame has been provided with a transition, while providing a midframe transition, only if the leading boundary of the frame has not been provided with a transition.

Claim 13

The method of encoding bivalued bits for recOrding the bits sequentially presented at a particular rate, corresponding to a particular bit rate frequency for recording in sequential bit frames, one bit per frame, comprising the steps of: converting each bit of a first value into a half-cycle pulse of a frequency half of the bit rate frequency to be recorded within a bit frame; converting each bit of a second value into a quarter-cycle pulse of one quarter the bit rate frequency to be recorded within a bit frame; and selecting the phase of a pulse in relation to the phase of the preceding pulse corresponding to two sequential bits to be recorded in sequential bit frames to have the same phase angle at the boundary between the two frames; a half-cycle pulse selected to extend from 0* to 180*, 180* to 360*, 90* to 270* or 270* to 90* , at the half-bit rate frequency, and covering the length of a bit frame, a quarter-cycle pulse selected to extend from 0* to 90*, 90* to 180* , 180* to 270* or 270* to 360* at the quarter bit rate frequency and covering the length of a bit frame.

Claim 14

The method of encoding bivalued bits for recOrding the bits sequentially presented at a particular rate, corresponding to a particular bit rate frequency for recording in sequential bit frames, one bit per frame, comprising the steps of: converting each bit of a first value into a half-cycle pulse of a frequency half of the bit rate frequency to be recorded within a bit frame; converting each bit of a second value into a quarter-cycle pulse of one quarter the bit rate frequency to be recorded within a bit frame; and selecting the phase of a pulse in relation to the phase of the preceding pulse corresponding to two sequential bits to be recorded in sequential bit frames to have the same phase angle at the boundary between the two frames; a half-cycle pulse selected to extend from 0* to 180*, 180* to 360*, 90* to 270* or 270* to 90* , at the half-bit rate frequency, and covering the length of a bit frame, a quarter-cycle pulse selected to extend from 0* to 90*, 90* to 180* , 180* to 270* or 270* to 360* at the quarter bit rate frequency and covering the length of a bit frame.

Claim 15

The method of encoding bivalued bits for recording, the bits sequentially presented at a particular rate corresponding to a particular bit rate frequency, for recording in sequential bit frames, one bit per frame, comprising the steps of: converting each bit of a first value into a half-cycle wave portion of a frequency half of the bit rate frequency, to be recorded within a bit frame; converting each bit of a second value into a quarter-cycle wave portion of a frequency of one quarter the bit rate frequency, to be recorded within a bit frame; and selecting the phase of each wave portion as beginning at a bit frame boundary to be larger by 90* than the selected phase angle of the wave portion as beginning at the preceding frame boundary.

Claim 16

The method of encoding bivalued bits for recording, the bits sequentially presented at a particular rate corresponding to a particular bit rate frequency, for recording in sequential bit frames, one bit per frame, comprising the steps of: converting each bit of a first value into a half-cycle wave portion of a frequency half of the bit rate frequency, to be recorded within a bit frame; converting each bit of a second value into a quarter-cycle wave portion of a frequency of one quarter the bit rate frequency, to be recorded within a bit frame; and selecting the phase of each wave portion as beginning at a bit frame boundary to be larger by 90* than the selected phase angle of the wave portion as beginning at the preceding frame boundary.