摘要:
Transmission of a high frequency signal is provided by a passive mixer. The passive mixer receives a low frequency signal as an input. The passive mixer includes a plurality of transistors each with a gate, a source, and a drain. The passive mixer also includes a local oscillator connected to the gates of the transistors. The gates of the transistors are also connected to a DC bias proportional to the threshold voltage of the transistors. In addition, an output of the passive mixer may be attenuated by a passive attenuator wherein both the passive attenuator and passive mixer are substantially free of quiescent current.
摘要:
Methods and corresponding systems in a low noise amplifier include selecting a selected sub-band for amplifying, wherein the selected sub-band is one of a plurality of sub-bands, wherein each sub-band is a portion of a frequency band, and wherein each sub-band has a corresponding sub-band center frequency. Next, a gate-source capacitor is adjusted so that a real part of an LNA input impedance corresponds to a real part of a source impedance at the selected sub-band center frequency. A match capacitor is also adjusted so that the LNA input impedance corresponds to the complex conjugate of the source impedance at the selected sub-band center frequency. The gate-source capacitor and the match capacitor can each be adjusted by recalling capacitor values from memory that correspond to the selected sub-band, and connecting selected capacitor components in response to the recalled capacitor values.
摘要:
An RF modulator supporting wide-band signals includes IQ modulation by interleaving the in-phase and quadrature signals. The modulator can be implemented using an integrated circuit having a baseband in-phase stage that receives an in-phase analog input signal, a baseband quadrature stage that receives a quadrature analog input signal, and a switching mixer having a plurality of switches. The switching mixer receives in-phase and quadrature signals from the baseband in-phase stage and the baseband quadrature stage. The switching mixer produces a differential signal combining the in-phase and quadrature signals by interleaving the signals over a plurality of phases of a carrier period.
摘要:
Method and apparatus are provided for high linearity and low noise communication signal mixing. The apparatus includes a high linearity low noise mixer having an input stage coupled to a switch stage by a series-coupled blocking capacitance and input resistance. The input stage includes a buffer with negative feedback, and the switch stage includes a transistor based switch network connected to an amplifier that has feedback resistance and shunting capacitance. The method includes AC coupling an RF signal, increasing a gain of the RF signal, reducing third-order distortion by negatively feeding-back the RF signal, blocking IM2 generated from said gain increasing step, increasing a second-order input intercept point (IIP2) by attenuating the RF signal across a resistance, and applying a local oscillator input to the RF signal.
摘要:
A modulated signal source for implementing A modulated signal method of a generating a modulated signal having a radio frequency based upon a linear mixing of signals is disclosed. An in-phase pulse signal modulator of the modulated signal source provides an in-phase pulse modulated signal in response to a reception of a baseband in-phase signal and an in-phase clock signal with the in-phase clock signal and the in-phase pulse modulated signal being synchronized. A quadrature pulse signal modulator of the modulated signal source provides a quadrature pulse modulated signal in response to a reception of a baseband quadrature signal and a quadrature clock signal with the quadrature clock signal and the quadrature pulse modulated signal being synchronized. A switch signal generator of the modulated signal source generates an in-phase switch signal and a quadrature switch signal in response to a reception of the in-phase clock signal, the in-phase pulse modulated signal, the quadrature clock signal, and the quadrature pulse modulated signal. The in-phase clock signal and the in-phase switch signal are synchronized, and the quadrature clock signal and the quadrature switch signal are synchronized. A radio frequency signal generator of the modulated signal source provides one or more modulated signals having a radio frequency in response to either a reception the in-phase switch signal and the quadrature phase signal, or a reception of a switch signal as a function of the in-phase switch signal and the quadrature phase signal.
摘要:
A device for implementing a method for generating a pulse width modulated signal based upon a natural sampling technique is disclosed. First, a complex baseband signal is received by the device. Second, the device computes a first pulse edge vector and a second pulse edge vector as a function of the baseband signal. Third, the device computes a first set of natural sampling points as a function of the first pulse edge vector and computes a second set of natural sampling points as a function of the second pulse edge vector. These computations can involve one or more detections of a jump k&pgr; within the first pulse edge vector and/or the second pulse edge vector. Finally, the pulse width modulated signal is generated with pulse edges corresponding to the first set of natural sampling points and the second set of natural sampling points.
摘要:
A device for implementing a method for receiving a complex baseband signal in analog form or in digital form, and providing a pulse modulated signal as a linear modulation of the complex baseband signal is disclosed. First, a complex modulated signal as a function of the complex baseband signal is generated. Second, a bandlimited exponential signal as a function of the complex modulated signal as computed with a truncated Taylor series for an exponential is generated, or a coefficient vector as a function of the complex modulated signal is generated. Finally, a pulse modulated signal as either a function of the bandlimited exponential signal or the coefficient vector is generated.
摘要:
A method and system of decimating a Pulse Width Modulated (PWM) signal (537) is provided. The method includes computing one or more timestamps (553) of the PWM signal (537), the PWM signal being at a first sample rate (567). The one or more timestamps (553) are computed at a second sample rate (568), which is lower than the first sample rate (567). Thereafter, the method generates a plurality of pre-filter signals (557-n) based on each of the one or more timestamps (553) and a plurality of translation factors (555-n). The plurality of pre-filter signals (557-n) is then filtered at the second sample rate (568) using a plurality of Infinite Impulse Response (IIR) filters (560-n) to generate a plurality of intermediate decimated Pulse Code Modulated (PCM) signals (563). The plurality of intermediate decimated PCM signals (563) is combined to generate a PCM signal (569).
摘要:
A method and system for operating a comparator (602) is provided. The method includes analyzing an output (612) of the comparator (602) based on one or more of a transition of the output, present operational state of the comparator, and at least one time instant corresponding to the output. The method further includes controlling an operational state of the comparator (602) based on the analysis of the output (612).
摘要:
A method and system of decimating a Pulse Width Modulated (PWM) signal (537) is provided. The method includes computing one or more timestamps (553) of the PWM signal (537), the PWM signal being at a first sample rate (567). The one or more timestamps (553) are computed at a second sample rate (568), which is lower than the first sample rate (567). Thereafter, the method generates a plurality of pre-filter signals (557-n) based on each of the one or more timestamps (553) and a plurality of translation factors (555-n). The plurality of pre-filter signals (557-n) is then filtered at the second sample rate (568) using a plurality of Infinite Impulse Response (IIR) filters (560-n) to generate a plurality of intermediate decimated Pulse Code Modulated (PCM) signals (563). The plurality of intermediate decimated PCM signals (563) is combined to generate a PCM signal (569).