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US 4,757,538 AGranted
Separation of L+R from L-R in BTSC system
AssigneeTektronix, Inc.
InventorScott E. Zink
Life of this patent
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Abstract
A stereo signal separation system for separating the L+R and L-R components of a BTSC stereo signal mixes the BTSC signal with a multiple of the pilot frequency. To recover the L+R component the mixer output is combined with the input BTSC signal, and to recover to L-R component the mixer output is combined with a second mixer output shifted ninety degrees. The combined output is low pass filtered to recover the desired component.
Claims5
A stereo signal separation system comprising:
- means for mixing an input stereo signal having a lower frequency sum component, an upper frequency double sideband suppressed carrier difference component and a pilot frequency at a frequency between the sum and difference components with a mixer frequency which is a multiple of the pilot signal frequency to produce a first mixer output and with a phase quadrature component of the mixer frequency to produce a second mixer output;
- means for combining the first and second mixer outputs to eliminate the sum component;
- and
- means for filtering the output of the combining means to recover the difference component.
1 more element
A stereo signal separation system comprising:
- means for mixing an input stereo signal having a lower frequency sum component, an upper frequency double sideband suppressed carrier difference component and a pilot frequency at a frequency between the sum and difference components with a mixer frequency which is a multiple of the pilot signal frequency to produce a mixer output;
- means for combining the input stereo signal and the mixer output to eliminate the difference component;
- and
- means for filtering the output of the combining means to recover the sum component.
1 more element
Dependencies are inferred from the claim text.