Abstract: A method and circuit for receiving a radio frequency signal by receiving and amplifying the radio frequency signal to produce a received signal and generating first and second clock signals corresponding to first and second channel signals, respectively, of the received signal and multiplying the received signal with the clock signals to obtain the channel signals. Pre-selectivity filtering of the received signal is performed by filtering the first channel using a first impedance, filtering the second channel using a second impedance, and converting the first and second impedances with respect to one another through a first gyrator. Amplitude limiting of the first and second channels is performed to obtain first and second amplitude limited channels. Poly-phase selectivity filtering of the first and second amplitude limited channels is performed to obtain first and second selectivity filtered channels. The selectivity filtered channels are demodulated to obtain a data signal.

Abstract: A circuit and method for differential slope demodulator circuit are shown that utilize amplitude stabilizing of a frequency modulated signal to obtain an amplitude stabilized signal. Also shown is bandpass filtering of the amplitude stabilized signal for a first frequency that is offset by a shift frequency below an intermediate frequency, to obtain a first filtered signal and bandpass filtering the amplitude stabilized signal for a second frequency that is offset by the shift frequency above the intermediate frequency, to obtain a second filtered signal. The circuit and method further operate by detecting an envelope of the first filtered signal to obtain a first envelope signal, detecting an envelope of the second filtered signal to obtain a second envelope signal, and differencing the first and second envelope signals to obtain a demodulated output signal.

Abstract: A logarithmic level detector that provides a very accurate level detector output signal that is greatly insensitive to temperature and process spread. The logarithmic level detector includes a weighted summed reference circuit which is subtracted from a level output signal of the cascade of limiting amplifiers so as to form a relative level detector output signal, and further compensation circuitry at input and output side, and an overall gain stabilizing circuit.

Abstract: An amplifier with a non-regenerative DC negative feedback loop which incorporates first and second first-order low-pass RC filters, has a signal path arranged from an input to an output and a feedback path arranged from the output to the input, and has a controlled loop gain. To provide substantially even selective amplification over a comparatively large tuning control range, the signal path incorporates one of the two RC filters and the feedback path incorporates the other RC filter together with the controlled loop gain; or the signal path incorporates the two RC filters together with one part of the controlled loop gain and the feedback path incorporates the other part of the controlled loop gain.

Abstract: Controllable oscillator circuit comprising a regenerative loop which incorporates a cascade circuit of first and second sections each having a controllable gain and a phase shift which is 90.degree. at the oscillation frequency, and an amplitude detection arrangement which is coupled between an output and a control input of at least one of the two sections.