Tracking receiver

Claim 2

In a receiver for tracking a signal radiated from a remote source, a tracking and acquisition loop comprising: a voltage controlled local oscillator; means for multiplying the frequency from the local oscillator by a pre-selected number; means for mixing the signal from said remote source with said multiplied signal so as to produce an IF signal; a cos-limited tangent phase detector having two pairs of input circuits and an output circuit, said cos-limited tangent phase detector being controlled such that the output signal therefrom is prevented from increasing in magnitude beyond a predetermined level; means for producing a pair of quadraturely phased reference signals at the IF frequency; means for feeding said IF signal and one of said reference signals to one pair of input circuits and for feeding said IF signal and the other of said IF signals to the other pair of input circuits of said cos-limited tangent phase detector; a filter; and means for feeding the output signal developed in the output circuit of said cos-limited tangent phase detector to the input of said filter and for feeding the output of said filter to the control element of said voltage controlled local oscillator.

Claim 3

In an arrangement as defined in claim 1 wherein said filter has a transfer function such that the loop in which it is disposed which includes said local oscillator, said means for multiplying the frequency thereof and said cos-limited tangent phase detector is a third-order loop.

Claim 4

In a receiver for tracking a signal radiated from a remote source and for locking on to said signal a phase-lock loop comprising, in combination a voltage controlled local oscillator; means for multiplying the frequency of the signal produced by said local oscillator by a preselected number; means for mixing the signal radiated by said remote source with said multiplied signal so as to produce an IF signal; a cos-limited tangent phase detector; means for generating a pair of quadraturely phased reference signals at the IF frequency; means for feeding said quadraturely phased reference signals and said IF signal to said cos-limited tangent phase detector, whereby an output signal generally corresponding to (1 + K) sin theta e/1 + F(K) cos theta e is produced where K is a constant and theta e is the phase error between said reference signal and said IF signal; means for controlling the operation of said cos-limited tangent phase detector such that the quantity 1 + F(K) cos theta e is prevented from equaling 0; a filter; and means for feeding the output signal from said cos-limited tangent phase detector to the input of said filter and for coupling the output thereof to the control element of said local oscillator, said filter, said local oscillator and said cos-limited tangent phase detector being part of a third order loop.

Claim 5

In a receiver for tracking a signal radiated from a remote source and for locking on to said signal a phase-lock loop comprising, in combination a voltage controlled local oscillator; means for multiplying the frequency of the signal produced by said local oscillator by a preselected number; means for mixing the signal radiated by said remote source with said multiplied signal so as to produce an IF signal; a cos-limited tangent phase detector; means for generating a pair of quadraturely phased reference signals at the IF frequency; means for feeding said quadraturely phased reference signals and said IF signal to said cos-limited tangent phase detector, whereby an output signal generally corresponding to (1 + K) sin theta e/1 + F(K) cos theta e is produced where K is a constant and theta e is the phase error between said reference signal and said IF signal; means for controlling the operation of said cos-limited tangent phase detector such that the quantity 1 + F(K) cos theta e is prevented from equaling 0; a filter; and means for feeding the output signal from said cos-limited tangent phase detector to the input of said filter and for coupling the output thereof to the control element of said local oscillator, said filter, said local oscillator and said cos-limited tangent phase detector being part of a third order loop.

Claim 6

In an arrangement as defined in claim 3 wherein said filter has a transfer function