Honeywell G.m.b.h.

Michael F Braitberg

Tzuo-Chang Lee

A magnetic record reproducing system preamplifier includes an inductive choke in the emitter circuit of a first stage transistor amplifier whereby to provide a frequency responsive variable input impedance whereby to maintain a proper impedance relationship between the inductive transducer and the input impedance of the first stage amplifier. A second stage transistor amplifier is connected to the output of the first stage amplifier in cascode relationship, reducing the effective voltage gain of the first stage to substantially zero. The choke in the input circuit of the first stage amplifier acts as a degenerative feedback at higher frequencies, effectively reducing the bias current through the first stage transistor. The base emitter capacitance of the first stage transistor tends to resonate with the inductance of the transducer. The effective degenerative feedback at that first stage transistor tends to push that resonant frequency beyond the desired or useful frequency band of the system.

Magnetic record reproducing system

A holographic recording is made on a tone wheel which is arranged to be driven by a capstan motor and capstan assembly. The holographic recording is a series of radial holograms on the tone wheel which recording is matched to the mechanical system driving the tone wheel by incorporating mechanical drive errors in the holographic recordings.

Method for making a holographic tone wheel for use in a sync-off-tach

A holographic recording is made on a tone wheel which is arranged to be driven by a capstan motor and capstan assembly. The holographic recording is a series of radial holograms on the tone wheel which recording is matched to the mechanical system driving the tone wheel by incorporating mechanical drive errors in the holographic recordings. The holographic recording on the tone wheel is read during subsequent operation of the motor/capstan/tone wheel assembly by a laser playback system to provide control signals for a motor energizing means to correct intrinsic drive system errors in a 'sync-off-tach' type tape drive system.

Error cancelling sync-off-tach tape drive system

A magnetic recording head driving circuit includes a single operational differential amplifier which mixes the bias signals with the data signals, the signal level of the two signals being separately controlled. The output of the amplifier is applied to the recording head through an impedance matching network. The impedance matching network converts the relatively high inductive impedance of the head to a substantially and effectively resistive load, matching the output impedance of the amplifier at the frequency of the bias signal.

Magnetic recording with bias and data mixing circuit

In a holographic memory or a holographic recording system, one dimensional Fourier transform holograms are recorded on a moving memory medium. The one dimensional Fourier transform holograms have their elongated dimension oriented in a direction which is essentially normal to the direction of motion of the memory medium

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Littleton, CO, United States of America

Michael F Braitberg