Frequency demodulation system

Claim 2

Means for demodulating a received encoded signal encoded with at least one predetermined pattern of successive signal segments of frequencies f 1 and f 2 , and comprising: first signal processing means responsive to said encoded signal and comprising first correlation means; said first correlation means comprising first register means containing a first staticized reference signal having a first pattern of binary 1's and 0's correlative with the signal segments of frequency f 1 to produce a first output signal when correlation occurs; second signal processing means responsive to said encoded signal and comprising second correlation means; said second correlation means comprising second register means containing a second staticized reference signal having a second pattern of binary 1's and 0's complementary to said first staticized pattern and correlative with the signal segments of frequency f 2 to produce a second output signal when correlation occurs; and means for combining said first and second output signals to produce a resultant output signal indicating correlation with said at least one pattern of signal segments.

Claim 3

Demodulating means as in claim 1 in which: said first signal processing means further comprises first filter means responsive to said encoded signal to output said signal segments of frequency f 1 to said first correlation means; in which said second signal processing means further comprises second filter means responsive to said encoded signal to output said signal segments of frequency f 2 to said second correlation means.

Claim 4

Demodulation means as in claim 1 in which: said first signal processing means further comprises first detecting means responsive to the output of said first correlation means to produce a first substantially two-level signal in response to said pattern with said first level representing the reception of signal segments of frequency f 1 and the second level representing the absence of signal segments of frequency f 1 ; and in which said second signal processing means further comprises second detector means responsive to the output of said second correlation means to produce a second substantially two-level signal in response to said pattern with said first level representing the reception of signal segments of frequency f 2 and said second level representing the absence of signal segments of frequency f 2 .

Claim 5

Demodulating means as in claim 1 in which: said first signal processing means further comprises first filtering and detecting means responsive to said encoded signal to output to said first correlation means a first substantially two-level signal in response to said pattern with a first level representing the reception of signal segments of frequency f 1 and the second level representing the reception of signal segments of frequency f 2 ; and in which said second signal processing means further comprises second filtering and detecting means responsive to said encoded signal to output to said second correlation means a second substantially two-level signal with a first level representing the reception of signal segments of frequency f 2 and with the second level representing the reception of signal segments of frequency f 1 .

Claim 6

Means for demodulating an encoded signal comprising first and second predetermined patterns of successive signal segments of frequencies f 1 and f 2 , and comprising: first signal processing means responsive to said encoded signal and comprising first correlation means; said first correlation means comprising first and second register means containing first and second staticized reference signals respectively having said first and second patterns of binary 1's and 0's correlative with the signal segments of frequency f 1 to produce first and second output signals when correlation occurs; second signal processing means responsive to said encoded signal and comprising second correlation means; said second correlation means comprising third and fourth register means containing third and fourth staticized reference signals respectively having said second and first patterns of binary 1's and 0's correlative with the signal segments of frequency f 2 to produce third and fourth output signals when correlation occurs; and means for combining said first and third output signals to produce a first resultant output signal indicating correlation with said first pattern of signal segments and for combining said second and fourth output signals to produce a second resultant signal indicating correlation with said second pattern of signal segments.

Claim 7

Means for demodulating an encoded signal comprising first and second predetermined patterns of successive signal segments of frequencies f 1 and f 2 , and comprising: first signal processing means responsive to said encoded signal and comprising first correlation means; said first correlation means comprising first and second register means containing first and second staticized reference signals respectively having said first and second patterns of binary 1's and 0's correlative with the signal segments of frequency f 1 to produce first and second output signals when correlation occurs; second signal processing means responsive to said encoded signal and comprising second correlation means; said second correlation means comprising third and fourth register means containing third and fourth staticized reference signals respectively having said second and first patterns of binary 1's and 0's correlative with the signal segments of frequency f 2 to produce third and fourth output signals when correlation occurs; and means for combining said first and third output signals to produce a first resultant output signal indicating correlation with said first pattern of signal segments and for combining said second and fourth output signals to produce a second resultant signal indicating correlation with said second pattern of signal segments.

Claim 8

Demodulation means as in claim 5 in which: said first signal processing means further comprises first filter means responsive to said encoded signal to pass said signal segments of frequency f 1 to said first correlation means; and in which said second signal processing means further comprises second filter means responsive to said encoded signal to pass said signal segments of frequency f 2 to said second correlation means.

Claim 9

Demodulating means as in claim 5 in which: said first signal processing means further comprises first filtering means and detecting means responsive to said encoded signal to output to said first correlation means first and second substantially two-level signals in response to said first and second patterns with a first level representing the reception of signal segments of frequency f 1 and the second level representing the reception of signal segments of frequency f 2 ; and in which said second signal processing means further comprises second filtering means and detecting means responsive to said encoded signal to output to said second correlation means third and fourth substantially two-level signals with a first level representing the reception of signal segments of frequency f 2 and with the second level representing the reception of signal segments of frequency f 1 .