Simultaneous signal detector for an instantaneous frequency measurement receiver
Sampling spectrum analyzer
Instantaneous frequency measurement receiver with digital processing
Alias tagging time domain to frequency domain signal converter
Digital frequency measurement receiver with bandwidth improvement through multiple sampling of real signals
Digital frequency measurement receiver with bandwidth improvement through multiple sampling of complex signals
Instantaneous frequency measurement receiver with bandwidth improvement through phase shifted sampling of real signals Patent #: 5109188
ApplicationNo. 726093 filed on 07/05/1991
US Classes:324/76.35, With delay line324/76.47, Digital output324/76.55, Digital output324/76.78, Quadrature sensing324/76.82, Digital output341/123, Having variable sampling rate342/196, Fast fourier transform (FFT)702/77Using Fourier method
ExaminersPrimary: Wieder, Kenneth A.
Assistant: Solis, Jose M.
International ClassG01R 023/00
AbstractThis is a technique for extending the frequency range which employs a power divider having two outputs, one output being supplied to a first A/D converter, and the other output being supplied via a delay device to a second A/D converter. A processor receives the outputs of the two A/D converters. In operation, the input signal is subjected to a known delay ͌ and both original and delayed signals are sampled simultaneously. Both sampled signals are Fourier transformed and the phase and amplitudes calculated, using the expressions:$c;(f)=tan-1 [I(f)/R(f)]A(f)=[R2 (f)+I2 (f)]1/2where R(f) and I(f) are respectively the real and imaginary parts of the frequency transform. The phase difference between the original and delayed signals is calculated and an approximation to the true frequency for each peak observed in the amplitude spectrum is estimated using the expression$c;=2πf͌where ͌ is the delay.In general, one would expect that when f͌<1, one can recover the input frequency. However, effects associated with the sampling limit the input bandwidth to f<1/͌. A specific sampling rate is used which can restore the unambiguous bandwidth tof<1/͌.