초록 ▼

Novel structure and methods for tuning the local oscillator of an optical superheterodyne receiver are disclosed. In a first method, the value of the local oscillator frequency at which the maximum of the chronological average of the output signal from the demodulator occurs is used to set the local

Novel structure and methods for tuning the local oscillator of an optical superheterodyne receiver are disclosed. In a first method, the value of the local oscillator frequency at which the maximum of the chronological average of the output signal from the demodulator occurs is used to set the local oscillator frequency. An alternate method first and second discriminators are used to receive the intermediate frequency signal. The separate discriminator characteristics of the first and second frequency discriminators are used in setting the local oscillator frequency.

대표청구항 ▼

An optical superheterodyne receiver comprising; an optical local oscillator for generating a local oscillator signal having a frequency which may be adjusted by a control signal; an optical coupler for superimposing a data signal and the local oscillator signal to generate an optical superimposed si

An optical superheterodyne receiver comprising; an optical local oscillator for generating a local oscillator signal having a frequency which may be adjusted by a control signal; an optical coupler for superimposing a data signal and the local oscillator signal to generate an optical superimposed signal; a means for acquiring an intermediate frequency signal from the optical superimposed signal; a demodulator for demodulating the intermediate frequency signal having a demodulator characteristic representing a time-independent output of the demodulator as a function of the intermediate frequency which exhibits a positive value at a first characteristic frequency of the data signal and a negative value at a second characteristic frequency of the data signal and wherein there is a monotonic drop from the positive value to the negative value with a zero-axis crossing midway between the first and second characteristic frequencies; a control means for controlling a frequency of the intermediate frequency signal by adjusting the frequency of the local oscillator with a control signal; a means for generating a chronological average of an output from the demodulator; and a means for determining the maximum of the chronological average and the corresponding value of local oscillator frequency at which this maximum occurs.