3 results about "Carrier leakage" patented technology

The application discloses a fast recovery power device with embedded tunnel diode structure and a production method thereof, wherein the power device has a plurality of uniformly arrayed heavy doped regions with opposite doped types under a neutral body region, and the heavy doped regions form a tunnel PN junction structure with the doped regions with opposite doped types in the neutral body region; the tunnel PN junction structure can provide an additional minority carrier leakage conduction channel when the power MOSFET device is switched from a conducting state to a closed state, reduces the tail current when the device is closed, makes the power device quickly closed from an open state, and thus improves the working speed of the device and expands the frequency band range of the power device. The application realizes the fast recovery characteristic of the device through the process steps of adding the arrayed opposite heavy doped regions and rapid thermal annealing, makes the power device have the advantages of low cost and fast recovery, and breaks the barrier that the VDMOS power device can only be used in the medium and low frequency field applications.

The application discloses a zero intermediate frequency satellite communication signal processing method and system based on an embedded microcontroller, and the method comprises the following steps: encoding and framing original data, generating I / Q digital baseband waveforms through QPSK mapping, upsampling and shaping filtering, and converting analog signals through a double-channel DAC. In view of Sinc fading and adjacent channel leakage caused by the zero-order holding effect of the DAC, two-stage cascade suppression is adopted: the first stage of attenuation is performed in the digital domain; the second stage of physical filtering is performed in the analog domain between the DAC and the mixer by using the stop band notch characteristic of the symmetrical active differential low-pass filter circuit, and the independent direct current bias adjustment is used for IQ balance adjustment to eliminate the carrier leakage. Finally, the mixer is used for one-step up-conversion, and a power amplifier is used for emission. The method does not need closed-loop digital IQ correction, significantly reduces resource consumption, and improves the adjacent channel power ratio and radio frequency quality.

Quantum cascade lasers (QCLs) are provided, which in embodiments comprise a plurality of stages, each stage comprising alternating quantum well layers and barrier layers, wherein each stage is configured, upon application of an electric field F across the plurality of stages, to inject carriers from a low energy state of an adjacent, upstream stage of the plurality of stages into a high energy state of a lasing stage of the plurality of stages, via tunneling injection through multiple barrier layers comprising barrier layers of the adjacent, upstream stage and barrier layers of the lasing stage, wherein carriers in the lasing stage undergo intraband transitions from an upper laser level of the lasing stage to at least one lower laser level of the lasing stage with the emission of laser light and without carrier leakage.