Abstract There is disclosed a circuit for measuring the frequency difference of two signals of the forms cos(wt+st) and cos(wt). A feedback signal theta is derived, and this feedback signal is operated upon together with the first input signal to derive a signal of the form cos(wt+st- theta ). This derived signal is compared to the second input signal in a phase comparator whose output is connected to the input of a high-gain amplifier. The amplifier output is the theta signal used in the first instance. Because of the employment of a high-gain amplifier in the loop, the output of the phase comparator is nulled. This, in turn, forces the two signals operated upon by the phase comparator to be equal so that theta st. By differentiating the theta signal, the frequency difference s can be derived. The same ''''phase-chasing'''' technique can be employed not only to measure the frequency shift introduced by a transmission channel to a complex signal but also to compensate for that frequency shift and for phase intercept distortion as well.
Inventors
👤 F Bradley
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-26 22:32
CPC Classifications
G; G01; G01R; G01R23/00
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
113 words
A circuit for deriving a measure of the frequency difference s of two signals of the form cos(wt + st) and cos(wt) comprising means for operating upon a signal theta and said cos(wt + st) signal to derive a signal of the form cos(wt + st - theta ), means for comparing the phases of said derived signal and said cos(wt) signal for producing a signal proportional to the difference in the phases thereof, and high-gain amplifying means for amplifying said produced signal, the output of said high-gain amplifying means being used as said theta signal such that said high-gain amplifying means forces said produced signal to be nulled so that theta st.
Claim 2
Dependent Claim
113 words
A circuit for deriving a measure of the frequency difference s of two signals of the form cos(wt + st) and cos(wt) comprising means for operating upon a signal theta and said cos(wt + st) signal to derive a signal of the form cos(wt + st - theta ), means for comparing the phases of said derived signal and said cos(wt) signal for producing a signal proportional to the difference in the phases thereof, and high-gain amplifying means for amplifying said produced signal, the output of said high-gain amplifying means being used as said theta signal such that said high-gain amplifying means forces said produced signal to be nulled so that theta st.
Claim 3
Dependent Claim
124 words
A circuit in accordance with claim 1 wherein said two signals are derived from the output of a transmission channel, the input to said transmission channel being a signal having two frequencies one of which is an integral multiple of the other, said transmission channel functioning to shift each of said two signals by the same frequency, and further including first filter means for transmitting therethrough only the higher-frequency component in the signal received along said transmission channel to derive the first of said two signals, second filter means for transmitting therethrough only the lower-frequency component in the received signal, and means for multiplying the signal transmitted through said second filter means by said integral multiple to derive the second of said two signals.
Claim 4
Dependent Claim
38 words
A circuit for compensating the frequency and phase shift introduced by a communication channel of each of many different frequency components in a complex signal, said complex signal after transmission along said communication channel being of the form
Claim 5
Dependent Claim
38 words
A circuit for compensating the frequency and phase shift introduced by a communication channel of each of many different frequency components in a complex signal, said complex signal after transmission along said communication channel being of the form