Playback system with frequency equalization by cascaded circuits performing in accordance with partial fraction expansions of factorial equalizing function terms

Claim 3

A method as claimed in claim 1, wherein: said playback system is a multi-speed playback system; and parameters of said function-performing means are switched for each speed of the playback system to adapt the equalization of said non-linear frequency response to the particular speed.

Claim 4

A method as claimed in claim 2, wherein: a parameter of one of said function-performing means is adjusted for each playback system speed to adapt the equalization of said non-linear frequency response to each playback system speed.

Claim 5

A method as claimed in claim 1, wherein: said non-linear frequency response substantially is a non-linear amplitude-versus-frequency response; said equalizing function is provided by providing an eQualizing function for said non-linear amplitude-versus-frequency response; said equalizing function is analyzed into a number of factorial amplitude equalization terms; a partial fraction expansion is performed on each factorial amplitude equalization term; a means is provided for each of said factorial amplitude equalization terms for performing in accordance with the particular partial fraction expansion a function conforming to the particular factorial amplitude equalization term; said equalizing function is provided with a further factorial term for correcting phase shifts introduced by said function-performing means; a partial fraction expansion is performed on said further factorial term; a further means is provided for performing in accordance with the partial fraction expansion performed on the further factorial term a function conforming to said further factorial term for correcting said phase shifts; the number of amplitude equalization means and the phase shift correcting means are cascaded; and said played-back electric signal is subjected to said cascaded amplitude equalization means and phase shift correcting means whereby to equalize said non-linear frequency response and correct said phase shifts.

Claim 6

A method as claimed in claim 4, wherein: said playback system is a multi-speed playback system; parameters of said amplitude equalization means are switched for each speed of the playback system to adapt the equalization of said non-linear frequency response to the particular speed.

Claim 7

A method as claimed in claim 5, wherein: a parameter of said phase shift correcting means is switched for each speed of the playback system to adapt the correction of said phase shifts to the particular speed.

Claim 8

A method as claimed in claim 6, wherein: a parameter of one of said amplitude equalization means is adjusted for each playback system speed to adapt the equalization of said non-linear frequency response to each playback system speeds.

Claim 9

In apparatus for playing back recorded signals and equalizing a non-linear frequency response of the playback with the aid of an equalizing function for an equalization of the non-linear frequency response, the improvement comprising in combination: means for playing back said recorded signals in the form of corresponding electric signals; a number of cascaded means for performing said equalizing function on said electric signals, said number of cascaded means including first means for performing on said electric signals a function conforming to a first factorial term of said equalizing function, and second means connected in cascade with said first means for performing a function conforming to a second factorial term of said equalizing function, said first means including third means for performing on said electric signals a function conforming to a first term of a partial fractional expansion of said first factorial term, and fourth means connected to said third means for performing on said electric signals a function conforming to a second term of said partial fractional expansion of said first factorial term, and said second means including fifth means for performing a function conforming to a first term of a partial fractional expansion of said second factorial term, and sixth means connected to said fifth means for performing a function conforming to a second term of said partial fractional expansion of said second factorial term; and means connected between said playback means and said number of cascaded means for applying said played-back electric signals to said number of cascaded means whereby said non-linear frequency response is equalized.

Claim 10

In apparatus for playing back recorded signals and equalizing a non-linear frequency response of the playback with the aid of an equalizing function for an equalization of the non-linear frequency response, the improvement comprising in combination: means for playing back said recorded signals in the form of corresponding electric signals; a number of cascaded means for performing said equalizing function on said electric signals, said number of cascaded means including first means for performing on said electric signals a function conforming to a first factorial term of said equalizing function, and second means connected in cascade with said first means for performing a function conforming to a second factorial term of said equalizing function, said first means including third means for performing on said electric signals a function conforming to a first term of a partial fractional expansion of said first factorial term, and fourth means connected to said third means for performing on said electric signals a function conforming to a second term of said partial fractional expansion of said first factorial term, and said second means including fifth means for performing a function conforming to a first term of a partial fractional expansion of said second factorial term, and sixth means connected to said fifth means for performing a function conforming to a second term of said partial fractional expansion of said second factorial term; and means connected between said playback means and said number of cascaded means for applying said played-back electric signals to said number of cascaded means whereby said non-linear frequency response is equalized.

Claim 11

An apparatus as claimed in claim 8, wherein: said playback means include multi-speed playback means for playing back recorded signals in the form of corresponding electric signals at different playback speeds; and said first and second means include selectively actuable means for adaptinG the equalization of said non-linear frequency response to each playback speed.

Claim 12

An apparatus as claimed in claim 9, wherein: said selectively actuable adapting means include selectively actuable resonant circuit means.

Claim 13

An apparatus as claimed in claim 9, wherein: said selectively actuable adapting means include means for adjusting the equalization of said non-linear frequency response for each playback speed.

Claim 14

An apparatus as claimed in claim 9, wherein: said selectively actuable adapting means include selectively actuable RC circuit means.

Claim 15

An apparatus as claimed in claim 9, wherein: said cascaded means include means tending to introduce phase shifts in said electric signals; said apparatus includes seventh means cascaded with said first and second means for correcting said phase shifts in said electric signals; and said seventh means include selectively actuable means for adapting the correction of said phase shifts to each playback speed.

Claim 16

An apparatus as claimed in claim 13, wherein: said phase shift correction means include selectively actuable RC circuit means for adapting the correction of said phase shifts to each playback speed.

Claim 17

An apparatus as claimed in claim 14, wherein: said selectively actuable adapting means include selectively adjustable means for adjusting the equalization of said non-linear frequency response for each playback speed.

Claim 18

An apparatus as claimed in claim 8, wherein: said playback system is a multi-speed playback system; one of said function-performing means includes transconductance amplifier means having a selectively actuable load impedance and having a selectively actuable further impedance, separate from said load impedance, for adapting the equalization of said non-linear frequency response to each playback speed.

Claim 19

An apparatus as claimed in claim 16, wherein: said load impedance includes selectively actuable resonant circuit means for adapting the frequency characteristic of the upper part of said non-linear frquency response to each playback speed.

Claim 20

An apparatus as claimed in claim 17, wherein: said further impedance includes selectively actuable gain adjustment means for adapting the gain of the upper part of said non-linear frequency response to each playback speed.

Claim 21

An apparatus as claimed in claim 18, wherein: another of said function-performing means includes a second transconductance amplifier means having a second selectively actuable load impedance, and having a second selectively actuable further impedance, separate from said second load impedance, for adapting the equalization of said non-linear frequency response to several playback speeds.