A low-speed digital signal modulation method and device

A technology of digital signal and modulation method, which is applied in the direction of AM carrier system, FM carrier system, phase modulation carrier system, etc. It can solve the problem that the anti-interference ability is not as good as phase shift keying and differential phase shift keying, etc., and achieve low power consumption , The effect of small circuit size

Inactive Publication Date: 2017-09-19
INST OF GEOLOGY & GEOPHYSICS CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

Frequency shift keying can distinguish channels, but the anti-interference ability is not as good as phase shift keying and differential phase shift keying

Method used

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  • A low-speed digital signal modulation method and device
  • A low-speed digital signal modulation method and device
  • A low-speed digital signal modulation method and device

Examples

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specific Embodiment

[0074] In this example, it is necessary to use BPSK mode for data modulation transmission, the carrier frequency is 1000Hz, the user data transmission frequency is 20bps (that is, the baseband frequency transmits 20 bits per second), each 1 bit occupies 5 (S) carrier signal periods, and when the transmission bit is 1 , the initial phase of the carrier signal is 0°, and the initial phase is 180° when sending 0.

[0075] The CPU used is STM32F407, and the internal resources include timer, power-down memory, memory, timer, direct memory access controller, and digital-to-analog converter. The analog voltage signal generated is output by the corresponding pin of the digital-to-analog converter. The digital-to-analog converter is 12 bits, and the maximum input value is 2 12 -1=4095(D DAC_MAX ).

[0076] Firstly, a cycle of sinusoidal data point table is generated, the number of internal points in a cycle is 200 (N), the minimum value is 0, and the maximum value is 4095. According...

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Abstract

The invention provides a low-speed digital signal modulation method and a low-speed digital signal modulation device. The low-speed digital signal modulation method is used in occasions with low transmission speed and low power consumption, is applicable to a plurality of modulation modes, and comprises the specific steps of: step 1, generating a sine data point table of one period, wherein the sine data point table is saved in a power-down storage; step 2, reading data points in the step 1 by means of a data preprocessing unit, and transmitting the data points to an established data buffer region unit, wherein the data buffer region unit is used for saving the data point temporarily, and the transmission of data bits is controlled by a first-path timer; step 3, transmitting the data in the data buffer region unit to a digital-to-analog converter at a certain time interval by means of a direct memory access controller, wherein the time interval is controlled by a second-path timer; step 4, converting a digital quantity into an analog voltage value and outputting the analog voltage value by means of the digital-to-analog converter; step 5, and filtering an analog quantity by means of a filter. The low-speed digital signal modulation method and the low-speed digital signal modulation device are applicable to some occasions with low signal transmission speed, limited installation space and low power consumption requirements.

Description

technical field [0001] The invention belongs to the field of digital communication, in particular to a low-speed digital signal modulation method and device. Background technique [0002] In digital communication, it is necessary to transmit messages in digital form, or to modulate the carrier signal in digital form and then transmit it. [0003] There are three basic digital modulation methods: Amplitude Shift Keying (ASK), Frequency Shift Keying (FSK) and Phase Shift Keying (PSK). Amplitude, frequency and phase modulation. [0004] Amplitude keying uses a digital modulation signal to control the on-off of the carrier. For example, in binary, the carrier is not sent when 0 is sent, and the carrier is sent when 1 is sent. Multilevel amplitude modulation representing multiple symbols is also sometimes referred to as amplitude keying. Amplitude keying is simple to implement, but has poor anti-interference ability. [0005] Frequency shift keying uses the positive and nega...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L27/04H04L27/08H04L27/12H04L27/16H04L27/20
CPCH04L27/04H04L27/08H04L27/12H04L27/16H04L27/20
Inventor 杨永友陈文轩王自力底青云孙云涛张文秀郑健
Owner INST OF GEOLOGY & GEOPHYSICS CHINESE ACAD OF SCI
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