Voltage mode amplifier for use with a high Q magnetic head
US4134140A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 1, 1976 |
| Grant date | Jan 9, 1979 |
| Priority date | — |
| Expiry date | Oct 1, 1996 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F1/52
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A high Q magnetic playback head applies its developed signal to the input of a voltage mode circuit. To facilitate equalizer design, the head is resistor-damped. While mere resistor damping reduces the Q of the head, it does so at the expense of the signal-to-noise ratio (SNR) of the head-and-amplifier circuit. To maintain SNR substantially without change, the amplifier employs a large resistance to which negative feedback is applied so the resistance appears as an effective resistance equal to its actual value divided by the amplifier gain. The value of this effective resistance is made to equal the magnetic playback head inductive reactance at the point of resonance, thereby reducing the head Q to approximately 1, and equalizer design is made easier.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.