Optimized structure for digital separation of composite video signals
View Patent ↗A device and method are provided for implementing digital baseband separation of composite video signals with reduced memory requirements. The method and device require that only the composite signal be stored in a large delay element. Multiple quadrature demodulators are employed to generate multiple delayed complex baseband signals. Therefore, no large complex baseband delay element is required.
1. A composite video signal separation device, comprising
a delay memory configured to store a composite signal and to output a plurality of delayed versions of said composite signal;
a plurality off demodulators coupled to said delay memory and configured to demodulate said plurality of delayed versions of said composite signal by a sub-carrier, and to generate a plurality of complex baseband signals;
a vertical signal processing block coupled to said plurality of demodulators and configured to process said plurality of complex baseband signals and to output a first separated signal;
a modulator coupled to said vertical signal processing block and configured to modulate said first separated signal and to generate a remodulated signal; and
a subtractor coupled to said modulator and configured to subtract said remodulated signal from one of said plurality of delayed versions of said composite signal and to generate a second separated signal.
2. A composite video signal separation device, comprising
a delay memory for storing a composite signal and configured to output a plurality of signals derived from said composite signal;
a plurality of demodulators coupled to said delay memory and configured to demodulate said plurality of signals derived from said composite signal by a sub-carrier to generate a plurality of complex baseband signals;
a vertical signal processor coupled to said plurality of and configured to process said plurality of complex baseband signals, and further configured to output a first separated signal and a second separated signal;
a modulator coupled to said vertical signal processor and configured to modulate said first separated signal and to generate a remodulated signal; and
a subtractor coupled to said modulator and configured to subtract said remodulated signal from one of said plurality of signals derived from said composite signal and to generate a third separated signal.
3. A composite video signal separation device, comprising
a delay memory for storing a composite signal and configured to output a plurality of signals derived from said composite signal;
a plurality of demodulators coupled to said delay memory and configured to demodulate said plurality of signals derived from said composite signal by a sub-carrier and to generate a plurality of demodulated signals;
a plurality of horizontal signal processing blocks coupled to said plurality of demodulators and configured to process said plurality of demodulated signals and to generate a plurality of complex baseband signals;
a vertical signal processor coupled to said plurality of horizontal signal processing blocks and configured to process said plurality of complex baseband signals and to output a first separated signal;
a modulator coupled to said vertical signal processing block and configured to modulate said first separated signal, and to generate a remodulated signal; and
a subtraction device coupled to said modulator and configured to subtract said remodulated signal from one of said plurality signals derived from said composite signal and to generate a second separated signal.
4. A method for composite video signal separation, comprising:
obtaining samples of a composite signal;
storing said samples in a delay memory;
demodulating a plurality of samples from said delay memory by a subcarrier to form a plurality of complex baseband signals;
vertically processing said plurality of complex baseband signals to form a first separated signal;
modulating said first separated signal by a subcarrier to form a remodulated signal; and
subtracting said remodulated signal from one of said samples of said composite signal to form a second separated signal.
5. A method for composite video signal separation, comprising:
obtaining samples of a composite signal;
storing said samples in a delay memory;
demodulating a plurality of samples from said delay memory by a subcarrier to form a plurality of complex baseband signals;
vertically processing said plurality of complex baseband signals to form a first separated signal and a second separated signal;
modulating said first separated signal by a subcarrier to form a remodulated signal; and
subtracting said remodulated signal from one of said samples of said composite signal to form a third separated signal.
6. A method for composite video signal separation, comprising
obtaining samples of a composite signal;
storing said samples in a delay memory;
demodulating a plurality of samples from said delay memory by a subcarrier to form a plurality of demodulated signals;
horizontally processing said plurality of demodulated signals to form a plurality of complex baseband signals;
vertically processing said plurality of complex baseband signals to form a first separated signal;
modulating said first separated signal by a subcarrier to form a remodulated signal; and
subtracting said remodulated signal from one of said samples of said composite signal to form a second separated signal.