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US RE29,529 EGranted
Equalization circuit
AssigneeAmpex Corporation
InventorAlastair M. Heaslett
Life of this patent
Estimating the term…
Abstract
A frequency equalization circuit includes an active filter circuit. The filter circuit differentiates the input signal. A plurality of adjustable resistances are connected to the differentiator corresponding to a plurality of operating or frequency ranges. A switch selects one resistance in accordance with one selected operating range to connect the filter circuit to an amplifier.
Claims21
An equalization circuit comprising:
- an input terminal ;
- amplifying means having an input connected to said input terminal ;
- filter circuit means having an output [connected] for connection to said input of said amplifying means and for providing a signal varying in amplitude with frequency at its output;
- a plurality of adjustable resistances corresponding to a plurality of operating ranges connected to the output of said filter circuit means for adjusting the signal amplitude provided by the output;
- and
- switch means for selectively connecting one of said plurality of adjustable resistances to said input of said amplifying means according to one selected operating range.
3 more elements
An equalization circuit comprising:
- an input terminal;
- a first amplifier having an input and an output;
- an input resistance connected between said input terminal and the input of said first amplifier;
- and,
- a filter circuit connected in parallel with said input resistance including:
- circuit means having an output to filter a signal received at said input terminal;
- a plurality of adjustable resistances connected to the output of said filter circuit means, each of said resistances selected according to a different one of a plurality of operating ranges for adjusting the amplitude of the signal provided by said filter circuit means;
- and,
- switch means connected between said plurality of adjustable resistances and the input of said first amplifier for selectively connecting said adjustable resistances to said first amplifier.
6 more elements
An equalization circuit, comprising:
- a. an input terminal for receiving an input signal to be equalized;
- b. a first amplifying means having an input and an output;
- c. a first means for connecting said first amplifying means to said input terminal and providing an output signal which is substantially in phase with said input signal;
- d. a phase shift circuit means coupled to said input terminal and providing an output signal having an increasing amplitude and constant phase lag with frequency relative to said input signal, within a predetermined frequency range of said input signal;
- e. a second means for connecting the output of said phase shift circuit means to said input of said first amplifying means;
- and
- f. said first amplifying means providing an output signal representative of the sum of said respective output signals provided by said first
- connecting means and said phase shift means.
5 more elements
An equalization circuit comprising:
- a. an input terminal for receiving an input signal to be equalized;
- b. a first amplifying means having an input and an output, said input of the first amplifying means coupled to said input terminal to receive a signal which is substantially in phase with said input signal;
- c. a second amplifying means having an input, an output, a feedback resistor connected between said output and input to provide negative feedback, and a capacitive reactive impedance means coupled between said input terminal and the input of said second amplifying means, said second amplifying means providing an output signal increasing in amplitude and having a constant phase lag with frequency relative to input signal within a predetermined frequency range of said input signal;
- and
- d. means for connecting the output of said second amplifying means to said input of said first amplifying means.
2 more elements
Dependencies are inferred from the claim text.