Multiple input signal modulator and method therefor

Claim 2

A multiple input signal modulator comprising: summing means; switch means for sequentially sampling said multiple signals and coupling the sampled signals to said summing means, means for continuously coupling fractions of each of said multiple signals to said summing means, the sampled signals in combination with the continuously coupled signals forming a composite signal at said summing means said composite signal from the standpoint of Fourier analysis having a d.c. component and higher harmonic components; band limiting filter means for rejecting a predetermined harmonic component and higher harmonics, said fractions being valued to increase the magnitude of said d.c. component to compensate for the missing harmonics of said composite signal eliminated by said filter means, modulatoroscillator means; and predistortion means coupling the output of said filter means to said modulator oscillator means for compensating for any nonlinearity in said modulator-oscillator means.

Claim 3

A modulator as in claim 1 where said magnitude of said d.c. component is increased to substantially equal the first harmonic component of said composite signal.

Claim 4

A modulator as in claim 1 where said switch means include solid state devices together with counter means driven by a crystal oscillator for driving said switch means at a frame frequency, omega .

Claim 5

A modulator as in claim 3 together with means for providing a pilot signal to said summing means including divider meanS for dividing omega by 2, low-pass filter means for filtering omega /2, and phase correction means for adjusting the phase of said filtered omega /2 to said frame frequency, omega .

Claim 6

A multiple input signal system for producing a composite filtered signal comprising: summing means; switch means for sequentially sampling said multiple signals and coupling the sampled signals to said summing means; means for continuously coupling fractions of each of said multiple signals to said summing means, the sampled signals in combination with the continuously coupled signals forming a composite signal at said summing means said composite signal from the standpoint of Fourier analysis having a d.c. component and higher harmonic components; band limiting filter means for rejecting a predetermined harmonic component and higher harmonics, said fractions being valued to increase the magnitude of said d.c. component to compensate for the missing harmonics of said composite signal eliminated by said filter means, said continuous coupling means including individual adjustment means, said filter means having a shaped response to vary the amplitudes of one or more allowed harmonic components for optimum phase linearity said fractions being adjusted to provide for optimum separation of said input signals said filter means having an output of said composite filtered signal.

Claim 7

A multiple input signal system for producing a composite filtered signal comprising: summing means; switch means for sequentially sampling said multiple signals and coupling the sampled signals to said summing means; means for continuously coupling fractions of each of said multiple signals to said summing means, the sampled signals in combination with the continuously coupled signals forming a composite signal at said summing means said composite signal from the standpoint of Fourier analysis having a d.c. component and higher harmonic components; band limiting filter means for rejecting a predetermined harmonic component and higher harmonics, said fractions being valued to increase the magnitude of said d.c. component to compensate for the missing harmonics of said composite signal eliminated by said filter means, said continuous coupling means including individual adjustment means, said filter means having a shaped response to vary the amplitudes of one or more allowed harmonic components for optimum phase linearity said fractions being adjusted to provide for optimum separation of said input signals said filter means having an output of said composite filtered signal.

Claim 8

A system as in claim 5 together with modulator-oscillator means coupled to the output of said filter means and predistortion means series coupled between said modulator-oscillator means and said output of said filter means for compensating for any nonlinearity in said modulator-oscillator means.

Claim 9

A system as in claim 5 where said switch means include solid state devices together with counter means driven by a crystal oscillator for driving said switch means at a frame frequency, omega .

Claim 10

A system as in claim 7 where said solid state devices are field effect transistors.

Claim 11

A system as in claim 7 together with means for providing a pilot signal to said summing means including divider means for dividing omega by 2, low-pass filter means for filtering omega /2, and phase correction means for adjusting the phase of said filtered omega /2 to said frame frequency, omega .

Claim 12

A system as in claim 5 where there are stereo input signals and said shaping includes rolloff of said filter means at its higher frequency end.

Claim 13

A system as in claim 5 where said fractions are also adjusted to compensate for variations in the coupling efficiency of said switch means.

Claim 14

A system as in claim 8 together with operational amplifiers having a low output impedance for coupling said input signals to said field effect transistors (FETs) said summing means including an operational amplifier having a high input impedance at its input to which said transistors are coupled whereby leakage through an open FET switch is absorbed through a closed FET switch and its associated low output impedance operational amplifier.

Claim 15

A system as in claim 5 where there are four input signals and said filter means rejects fifth and higher harmonic components.

Claim 16

A system as in claim 13 where said shaping includes a 2dB gain at the third harmonic component.

Claim 17

A system as in claim 13 where said shaping includes a 0.5dB loss at the second harmonic component.