公开(公告)号：WO1981001342A1

公开(公告)日：1981-05-14

申请号：PCT/US1980001476

申请日：1980-10-31

Applicant: AMPEX CORP

Inventor： AMPEX CORP ,  TIN L

IPC: G11B05/47

CPC classification number: G11B5/03

Abstract: A digital circuit for generating a linearly increasing signal is provided for controlling the level of a recording A.C. bias signal. The digitally controlled bias signal (24) is mixed (48) with an analog signal of a known frequency and constant level and recorded (41). The circuit detects and stores a recording bias level corresponding to a reproduce signal envelope level (54), equal to an obtained peak level (56) adjusted with respect to a known overbias level (58). The circuit compensates (20) the detected recording bias level with respect to distance between the recording and reproducing heads (41, 42) to obtain an optimum recording bias level. The detected bias level remains stored (18) and unchanged during power supply interruption.

公开(公告)号：EP0093200A3

公开(公告)日：1985-08-14

申请号：EP82111445

申请日：1982-12-10

Applicant: International Business Machines Corporation

Inventor： Klaassen, Klaas B.

IPC: G11B05/09 ,  G11B05/58 ,  G11B05/47

CPC classification number: G11B5/5965 ,  G11B5/02 ,  G11B5/03

Abstract: A method for recording high frequency signals representing data with simultaneous readout of low frequency information, such as servo information prerecorded on a magnetic disk (22), comprises the step of modulating (12) with the data (14) a carrier signal (10) having a repetition frequency displaced significantly from the baseband of the data. The nonlinearity of the recording channel shifts the modulated signal spectrum into the low frequency baseband so that the data is magnetically recorded while the low frequency prerecorded information is read out.

公开(公告)号：EP0091229A3

公开(公告)日：1984-01-18

申请号：EP83301594

申请日：1983-03-22

Applicant: AMPEX CORPORATION

Inventor： Fawkes, John S.

IPC: G11B05/47 ,  G11B05/02

CPC classification number: G11B5/02 ,  G11B15/12 ,  H03K17/6877

Abstract: An electronic switching circuit coupled between a magnetic head driving circuit (3) and transducing windings (7) utilizing an electronic switch (6) whose internal resistance changes substantially linearly in response to an increasing or decreasing control signal. Particularly useful in magnetic bias recording or erase circuits to eliminate erase of useful information and recording of disturbing noise spikes due to induced high frequency noise signal when the switch is activated.