Method and system for rejecting single-sided leakage into an amplitude modulated (AM) channel
View Patent ↗Aspects of the method and system for rejecting single sided leakage into an amplitude modulated channel may comprise an AM demodulator for demodulating a received composite broadcast signal's control channel to generate an amplitude modulated (AM) component. A PM demodulator may demodulate a received composite broadcast signal's control channel to generate a phase modulated (PM) component. At least one subtractor may subtract an AM leakage component and a PM leakage component contributed by the single sided leakage in the received composite broadcast signal's control channel. The system may comprise at least one of each of AM and PM bandpass filters and envelope detectors that filter and detect envelopes of the AM and PM components at 982.5 Hz and 922.5 Hz.
1. A method for rejecting single sided leakage into an amplitude modulated (AM) channel, the method comprising:
demodulating a received composite broadcast signal's control channel containing single sided leakage to generate an amplitude modulated (AM) component and a phase modulated (PM) component; and
subtracting an AM leakage component and a PM leakage component from said AM component and said PM component, said AM leakage component and said PM leakage component contributed by the single sided leakage in the received composite broadcast signal's control channel.
2. The method according to claim 1 , comprising AM demodulating said received composite broadcast signal's control channel to generate said AM component.
3. The method according to claim 1 , comprising PM demodulating said received composite broadcast signal's control channel to generate said PM component.
4. The method according to claim 1 , comprising band pass filtering and detecting envelopes of said AM component at 982.5 Hz and 922.5 Hz.
5. The method according to claim 1 , comprising band pass filtering and detecting envelopes of said PM component at 982.5 Hz and 922.5 Hz.
6. The method according to claim 1 , comprising locking onto a carrier of the AM channel prior to said demodulating of said received composite broadcast signal's control channel.
7. The method according to claim 1 , wherein said demodulated received composite broadcast signal is dual-mono or stereo.
8. The method according to claim 1 , comprising band pass filtering said received composite broadcast signal's control channel.
9. The method according to claim 1 , comprising determining whether said demodulated received composite broadcast signal is stereo or dual-mono.
10. The method according to claim 1 , comprising determining whether said received composite broadcast signal is monaural (mono).
11. A machine-readable storage having stored thereon, a computer program having at least one code section for rejecting single sided leakage into an amplitude modulated channel, the at least one code section being executable by a computer for causing the computer to perform steps comprising:
demodulating a received composite broadcast signal's control channel containing single sided leakage to generate an amplitude modulated (AM) component and a phase modulated (PM) component; and
subtracting an AM leakage component and a PM leakage component from said AM component and said PM component, said AM leakage component and said PM leakage component contributed by the single sided leakage in the received composite broadcast signal's control channel.
12. The machine-readable storage according to claim 11 , comprising code for AM demodulating said received composite broadcast signal's control channel to generate said AM component.
13. The machine-readable storage according to claim 11 , comprising code for PM demodulating said received composite broadcast signal's control channel to generate said PM component.
14. The machine-readable storage according to claim 11 , comprising code for band pass filtering and detecting envelopes of said AM component at 982.5 Hz and 922.5 Hz.
15. The machine-readable storage according to claim 11 , comprising code for band pass filtering and detecting envelopes of said PM component at 982.5 Hz and 922.5 Hz.
16. The machine-readable storage according to claim 11 , comprising code for locking onto a carrier of the AM channel prior to said demodulating of said received composite broadcast signal's control channel.
17. The machine-readable storage according to claim 11 , wherein said demodulated received composite broadcast signal is dual-mono or stereo.
18. The machine-readable storage according to claim 11 , comprising code for band pass filtering said received composite broadcast signal's control channel.
19. The machine-readable storage according to claim 11 , comprising code for determining whether said demodulated received composite broadcast signal is stereo or dual-mono.
20. The machine-readable storage according to claim 11 , comprising code for determining whether said received composite broadcast signal is monaural (mono).
21. A system for rejecting single sided leakage into an amplitude modulated channel, the system comprising:
an AM demodulator for demodulating a received composite broadcast signal's control channel containing single sided leakage, to generate an amplitude modulated (AM) component;
a PM demodulator for demodulating said received composite broadcast signal's control channel containing single sided leakage, to generate an phase modulated (PM) component; and
at least one circuit that removes an AM leakage component and a PM leakage component from said AM component and said PM component, said AM leakage component and said PM leakage component contributed by the single sided leakage in the received composite broadcast signal's control channel.
22. The system according to claim 21 , comprising at least one AM bandpass filter and envelope detector that filters and detects envelopes of said AM component at 982.5 Hz and 922.5 Hz.
23. The system according to claim 21 , comprising at least one PM bandpass filter and envelope detector that filters and detects envelopes of said PM component at 982.5 Hz and 922.5 Hz.
24. The system according to claim 21 , comprising at least one phase lock loop (PLL) that locks onto a carrier of the AM channel prior to said demodulating of said received composite broadcast signal's control channel.
25. The system according to claim 21 , wherein said demodulated received composite broadcast signal is dual-mono or stereo.
26. The system according to claim 21 , comprising at least one band pass filter that band pass filters said received composite broadcast signal.
27. The system according to claim 21 , comprising a mode decision circuit that determines whether said demodulated received composite broadcast signal is stereo or dual-mono.
28. The system according to claim 21 , comprising a mode decision circuit that determines whether said received composite broadcast signal is monaural (mono).
29. The system according to claim 21 , wherein said at least one circuit that removes said AM leakage component and said PM leakage component is a subtractor.