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US3909527A
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Frequency shift keying system and method
Assignee: Mitsubishi Electric Corp
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Filing: 1973-09-18
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Granted: 1975-09-30
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Expires: 1993-09-18
Abstract
Abstract A frequency shift keying method which comprises the steps of transmitting N signals having different shift patterns which correspond to N code elements and whose frequency is varied in the entire allocated frequency band during one clock period, comparing N heterodyne detector outputs provided by N local signals for receiving, having each frequency shift pattern synchronized to N transmitting signals, each of said local signals having a constant frequency difference from the transmitting signals, and detecting the heterodyne detector circuit having the maximum output whereby the transmitted code element is detected and reproduced.
Inventors
- 👤 Takahisa Ohta
- 👤 Shigeo Sugimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 13:40
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/005; H04L; H04L27/00; H04L27/10
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
104 words
A frequency shift keying method, which comprises the steps of: transmitting N types of signals having different shift patterns which correspond to N values of code elements (N > OR = 2) in substantially the whole allocated band during one clock period; comparing N types of heterodyne detector outputs provided by N types of local signals for receiving, having each frequency shift pattern synchronized to N types of the transmitting signals, an said local signals each having a constant frequency difference from the transmitting signals; and detecting the heterodyne detectOr circuit having the maximum output whereby the transmitted code element is detected and reproduced.
Claim 2
Dependent Claim
104 words
A frequency shift keying method, which comprises the steps of: transmitting N types of signals having different shift patterns which correspond to N values of code elements (N > OR = 2) in substantially the whole allocated band during one clock period; comparing N types of heterodyne detector outputs provided by N types of local signals for receiving, having each frequency shift pattern synchronized to N types of the transmitting signals, an said local signals each having a constant frequency difference from the transmitting signals; and detecting the heterodyne detectOr circuit having the maximum output whereby the transmitted code element is detected and reproduced.
Claim 3
Dependent Claim
35 words
The frequency shift keying method according to claim 1, wherein said transmitting signals corresponding to each of said code elements and said local signals are formed by programmed frequency dividing from a reference frequency oscillator.
Claim 4
Dependent Claim
42 words
The frequency shift keying method according to claim 2, wherein each programmed frequency signal is provided by composing the output of a programmed frequency divider for frequency-dividing the output of said reference frequency oscillator and the output of a fixed frequency divider.
Claim 5
Dependent Claim
29 words
The frequency shift keying method according to claim 3, wherein each said programmed frequency divider is controlled by different pattern programs depending upon particular code elements and local signals.
Claim 6
Dependent Claim
27 words
The frequency shift keying method according to claim 3, wherein said fixed frequency divider has different frequency dividing ratios depending upon particular code elements and local signals.
Claim 7
Dependent Claim
98 words
A frequency shift keying method, which comprises the steps of: transmitting two types of signals having different shift patterns which correspond to two code elements in substantially the whole allocated band during one clock period; comparing two types of heterodyne detector outputs provided by two types of local signals for receiving, having frequency shift patterns synchronized to said two types of the transmitting signals, respectively, and said local signals each having a constant frequency difference from said transmitting signals; and detecting the heterodyne detector circuit having the maximum output whereby the transmitted code element is detected and reproduced.
Claim 8
Dependent Claim
98 words
A frequency shift keying method, which comprises the steps of: transmitting two types of signals having different shift patterns which correspond to two code elements in substantially the whole allocated band during one clock period; comparing two types of heterodyne detector outputs provided by two types of local signals for receiving, having frequency shift patterns synchronized to said two types of the transmitting signals, respectively, and said local signals each having a constant frequency difference from said transmitting signals; and detecting the heterodyne detector circuit having the maximum output whereby the transmitted code element is detected and reproduced.
Claim 9
Dependent Claim
136 words
A frequency shift keying method for the transmission of N values of code elements (N > or = 2), which comprises the steps of: dividing the allocated frequency band into N sub-bands having substantially the same width: distributing each sub-band to each of said code elements; transmitting signals having different shift patterns which correspond to each of said code elements and which vary in each whole distributed sub-band during one clock period; comparing N types of heterodyne detector outputs provided by N types of local signals for receiving, having each of said frequency shift patterns synchronized to said N types of transmitting signals, and said local signals each having a constant frequency difference from said transmitting signals; and detecting the heterodyne detector circuit having the maximum output, whereby the transmitted code element is detected and reproduced.
Claim 10
Dependent Claim
136 words
A frequency shift keying method for the transmission of N values of code elements (N > or = 2), which comprises the steps of: dividing the allocated frequency band into N sub-bands having substantially the same width: distributing each sub-band to each of said code elements; transmitting signals having different shift patterns which correspond to each of said code elements and which vary in each whole distributed sub-band during one clock period; comparing N types of heterodyne detector outputs provided by N types of local signals for receiving, having each of said frequency shift patterns synchronized to said N types of transmitting signals, and said local signals each having a constant frequency difference from said transmitting signals; and detecting the heterodyne detector circuit having the maximum output, whereby the transmitted code element is detected and reproduced.
Claim 11
Dependent Claim
35 words
The frequency shift keying method according to claim 7, wherein said transmitting signals corresponding to each of said code elements and said local signals are formed by program frequency dividing from a reference frequency oscillator.
Claim 12
Dependent Claim
137 words
A frequency shift keying method for transmitting a mark signal and a space signal, which comprises the steps of: dividing the allocated frequency band into two sub-bands having substantially the same width; distributing each sub-band to said mark signal and said space signal; transmitting signals having different shift patterns which correspond to said mark signal and said space signal and which vary in each whole distributed sub-band during one clock period; comparing two types of heterodyne detector outputs provided by two types of local signals for receiving, having each of said frequency shift patterns synchronized to said two types of transmitting signals, and said local signals each having a constant frequency difference from said transmitting signal; and detecting the heterodyne detector circuit having the higher output, whereby said transmitted mark or space signal is detected and reproduced.
Claim 13
Dependent Claim
137 words
A frequency shift keying method for transmitting a mark signal and a space signal, which comprises the steps of: dividing the allocated frequency band into two sub-bands having substantially the same width; distributing each sub-band to said mark signal and said space signal; transmitting signals having different shift patterns which correspond to said mark signal and said space signal and which vary in each whole distributed sub-band during one clock period; comparing two types of heterodyne detector outputs provided by two types of local signals for receiving, having each of said frequency shift patterns synchronized to said two types of transmitting signals, and said local signals each having a constant frequency difference from said transmitting signal; and detecting the heterodyne detector circuit having the higher output, whereby said transmitted mark or space signal is detected and reproduced.
References Cited (Backward Citations)
US3493865A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-29 | 1979-03-31 | 1979-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-29 | 1983-03-31 | 1983-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-29 | 1987-03-31 | 1987-09-30 | $7700.00 | Window Closed / Lapsed |