3results about How to "Increase data rate" patented technology

The present application relates to a kind of vibration velocity demodulation systems of laser doppler vibrometer, the laser doppler vibrometer includes laser vibration measurement and laser ranging two modes, the probe of laser vibration measurement mode is converted into beat frequency electric signal after the frequency shift laser interference signal collected and exports, including high-precision heterodyne conditioning circuit, the down-conversion module with multiplier, high-speed ADC circuit and high-speed acquisition and demodulation module, its down-conversion module includes analog multiplier, first switch, second switch and the measurement channel of different down-conversion frequency suitable for low vibration speed, the first input end of analog multiplier is connected after the intermediate frequency signal processed by high-precision heterodyne conditioning circuit, other end is connected with second switch.This application simultaneously provides the vibration velocity demodulation method for realizing the vibration velocity demodulation system of the described.

The application discloses a Bluetooth transmission method and system, the method comprises the following steps: sending a plurality of Bluetooth data packets while detecting Bluetooth connection; after sending the Bluetooth data packet each time, judging whether the ACK response is correctly received; if yes, increasing the initial maximum transmission window of Bluetooth in response to the correct reception of the ACK response; if not, using dichotomy to find the optimal window size of the current transmission between the initial maximum transmission window and the transmission window threshold, the transmission window threshold being smaller than the initial maximum transmission window; repeatedly calculating the optimal window size of several transmissions, and determining the best Bluetooth transmission window based on the optimal window size of several transmissions for data transmission; the application can improve the efficiency of Bluetooth transmission data.

The application provides a narrowband modulation and demodulation method and system suitable for cross-border magnetic induction communication, and belongs to the field of magnetic induction communication. ‑2 The application provides a minimum shift keying (QM-VMSK / 2) encoding modulation method based on quadrature modulation, which realizes parallel transmission through quadrature modulation to double the data rate under the condition of keeping the same bandwidth as the minimum shift keying (VMSK) encoding modulation signal; and a decoding method based on double-phase code detection, which has better anti-noise interference ability compared with the detection method based on zero-crossing detection and double-phase code pulse width discrimination, and has a signal-to-noise ratio gain of more than 2.5 dB when the bit error rate is 10 ‑2 The QM-VMSK / 2 modulation and demodulation technology can provide a narrowband modulation method for underwater magnetic induction communication, reduce the distortion of high-rate signals in the underwater dispersion channel, realize high-rate cross-border magnetic induction communication under the condition that the carrier frequency and the data rate have the same order of magnitude, and improve the communication range x data rate performance limit of magnetic induction communication.