Methods and systems are described for asynchronously measuring an equalized information signal to obtain amplitude information, modifying frequency dependent parameters of a continuous-time linear equalization (CTLE) component of the signal path, determining a correlation between CTLE parameters and signal amplitude, and adjusting, responsive to the correlation, a continuous-time linear equalization (CTLE) code of a CTLE to adjust equalization of the equalized information signal.

The disclosed embodiments relate to the design of an equalizer that uses both cross-coupled cascodes and inductive peaking to reduce distortion in a signal received from a communication channel by attenuating lower frequencies and amplifying higher frequencies. At lower frequencies, when the effects of inductive impedance within the equalizer are negligible, the equalizer essentially functions as a traditional cascode amplifier that presents high gain. At higher frequencies, the increases in inductive impedances within the equalizer act to boost a gain of the equalizer.

Methods and devices for reducing gate node instability of a differential cascode amplifier are presented. Ground return loops, and therefore corresponding parasitic inductances, are eliminated by using voltage symmetry at nodes of two cascode amplification legs of the differential cascode amplifier. Series connected capacitors are coupled between gate nodes of pairs of cascode amplifiers of the two cascode amplification legs so to create a common node connecting the two capacitors. In order to reduce peak to peak voltage variation at the common node under large signal conditions, a shunting capacitor is connected to the common node.

The present invention discloses a signal output circuit having DC gain maintaining mechanism used in an image signal transmission apparatus that includes a front-stage driving circuit and a back-stage driving circuit. The front-stage driving circuit includes a continuous time linear equalizer (CTLE) having an adjusting capacitor and configured to receive a digital input signal to perform a high frequency enhancement thereon to increase a bandwidth of the digital input signal to generate a front-stage output signal. The back-stage driving circuit includes a CTLE without the adjusting capacitor and configured to increase a DC gain of the front-stage output signal to compensate a DC gain drop between the front-stage output signal and the digital input signal to generate a back-stage output signal to an image signal receiving apparatus.

Methods and systems are described for asynchronously measuring an equalized information signal to obtain amplitude information, modifying frequency dependent parameters of a continuous-time linear equalization (CTLE) component of the signal path, determining a correlation between CTLE parameters and signal amplitude, and adjusting, responsive to the correlation, a continuous-time linear equalization (CTLE) code of a CTLE to adjust equalization of the equalized information signal.

According to one embodiment, a transformer-based in-phase and quadrature (IQ) includes a differential balun having a first inductor and a second inductor. The first inductor has a first input terminal and a first output terminal. The second inductor has a second input terminal and a second output terminal. Additionally, the IQ generator circuit includes a third inductor magnetically coupled with the first inductor. The third inductor has a first isolation terminal and a third output terminal. The IQ generator circuit also includes a fourth inductor magnetically coupled with the second inductor. The fourth inductor has a second isolation terminal and a fourth output terminal. The IQ generator circuit additionally includes a first transistor coupled to the first input terminal of the first inductor. Further, the generator circuit includes a second transistor coupled to the second input terminal of the second inductor. The first transistor, the second transistor, the first inductor, and the second inductor form a part of a differential amplifier.

A variable gain amplifier circuit includes first and second input terminals, first and second output terminals, first and second transistors respectively having bases electrically connected to the first and second input terminals and having collectors electrically connected to the first and second output terminals, and a degeneration circuit connected between emitters of the first and second transistors. The degeneration circuit has first and second MOS transistors each having two current terminals connected in series between the emitters of the first and second transistors, series resistor circuits, first and second current sources, two resistive elements connected between the first and second current sources and gates of the first and second MOS transistors, and two resistive elements connected between the first and second current sources and two nodes of the series resistor circuits.

Methods and systems are described for asynchronously measuring an equalized information signal to obtain amplitude information, modifying frequency dependent parameters of a continuous-time linear equalization (CTLE) component of the signal path, determining a correlation between CTLE parameters and signal amplitude, and adjusting, responsive to the correlation, a continuous-time linear equalization (CTLE) code of a CTLE to adjust equalization of the equalized information signal.

A low-power double-quadrature receiver is disclosed. The double-quadrature receiver includes a quadrature signal generator configured to generate a first quadrature signal and a second quadrature signal based on each component of a differential input signal, and a switching stage configured to perform down-conversion on the first quadrature signal and the second quadrature signal.

Equalizing an input signal according to a receiver equalizer peaking circuit having a capacitor FET (CFET) providing a capacitive value and a resistor FET (RFET) providing a resistive value, generating a capacitor control voltage at a gate of the CFET using a capacitor controller DAC based on a first reference voltage, and a RFET control voltage at a gate of the RFET using a resistor controller DAC based on a second reference voltage, generating the first reference voltage using a replica input FET, the first reference voltage varying according to a threshold voltage (Vt) of an input FET, providing the first reference voltage to the capacitor controller DAC, generating the second reference voltage using a replica RFET, the second reference voltage varying with respect to the first reference voltage and a Vt of the replica of the RFET, and providing the second reference voltage to the resistor controller DAC.