4 results about "Fixed frequency" patented technology

The invention discloses an asynchronous serial port communication baud rate automatic detection device and method. The detection device comprises an edge detection module, a pulse width counting module, a minimum pulse width module and a table look-up module which are connected in sequence. The detection method comprises the following steps: receiving an asynchronous serial port signal, and sampling the asynchronous serial port signal through a sampling clock signal with a fixed frequency to obtain a rising edge signal and a falling edge signal of the asynchronous serial port signal; generating a counting enable signal according to the rising edge signal or the falling edge signal, and obtaining the effective time length of the enable signal in real time to obtain a high-level or low-levelbit width count value; comparing the high-level or low-level bit width count value with the minimum pulse width count value, and outputting a smaller value ; and querying a Baud rate and bit width relation table stored in the minimum pulse width module according to the value output by the minimum pulse width module to obtain the Baud rate of the asynchronous serial port sending data.

The invention relates to the field of signal transmission, and particularly relates to an N-ary based digital signal transmission method. The N-ary based digital signal transmission method comprises the steps of dividing signals into reference signals and data signals, setting the amplitude range of the data signals to be Fmin-Fmax, transmitting the reference signals according to preset fixed frequency and preset fixed amplitude FA, wherein the fixed amplitude FA=Fmin+(Fmax-Fmin ) / N+Epsilon, and the Epsilon is greater than or equal to 0 and less than or equal to (Fmax-Fmin) / N; and transmitting the data signals according to the same frequency as the reference signals, wherein the amplitude of the data signals is set to be Fn=FA+(n-1)[(Fmax-Fmin) / N]+delta according to a number n to be transmitted at the same time, the n is greater than or equal to 0 and less than N, the N is a natural number which is greater than 2, the delta is greater than or equal to 0 and less than or equal to (Fmax-Fmin) / N, and the FA does not equal to 0. The transmission efficiency of the method provided by the invention on a transmission line is a plurality of times of the transmission efficiency of a binary system, thereby greatly improving the signal transmission efficiency. Meanwhile, the signals are extracted by adopting a differential mode, the signal to noise ratio in the signal transmission process is improved, the anti-interference ability is improved, and various transmitting modes such that the reference signals and the data signals are transmitted synchronously, at intervals and the like can be adopted selectively in the transmission process.