Measuring device capable of generating custom data files for quadrature amplitude modulation signals and its modulation method

Abstract

The invention discloses a measuring device capable of generating a user-defined data file orthogonal amplitude modulation signal and a modulation method. The measuring device includes a system control unit, an orthogonal amplitude modulation unit and an orthogonal amplitude control unit, and when an orthogonal amplitude modulation source is a user-defined data file, a baseband rate control module generates an original file baseband clock and an original file modulation clock according to a baseband rate value and a modulation mode; a storage control module generates original file baseband data according to the original file baseband clock and the user-defined data file; a bit width conversion module performs bit width conversion on the original file baseband data according to the modulation mode and the original file modulation clock, so as to generate original file to-be-modulated data; and a mapping module generates plural user-defined data file modulation signals according to the original file to-be-modulated data and constellation data. According to the measuring device and modulation method provided by the invention, when the modulation source is the user-defined data file, software resources can be saved, and response time can be shortened.

Description

technical field [0001] The invention relates to the field of test and measurement, in particular to a measuring device capable of generating a quadrature amplitude modulation signal of a self-defined data file and a quadrature amplitude modulation method thereof. Background technique [0002] Quadrature Amplitude Modulation (Quadrature Amplitude Modulation, hereinafter referred to as QAM) is an efficient digital modulation and demodulation method. Compared with other modulation technologies, this modulation technology can make full use of the bandwidth, has a high frequency utilization rate, and is resistant to Noise ability is strong. Therefore, it is widely used in medium and large capacity digital microwave communication systems, high-speed data transmission of cable television networks, and satellite communications. QAM is a kind of vector modulation. The baseband signal to be modulated is first mapped onto a complex plane (constellation diagram) to form 2-way complex m...

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Problems solved by technology

Therefore, the above processing flow brings the following problems: the processing time of the central processing unit to read, map, and write is relatively long, which makes the response time slow when modifying the modulation mode or modifying the custom data file, and takes up a lot of central processing time. The resources of the processor unit; and, when mapping a custom data file, such as 8QAM, then the value of the 3-bit custom data file should be mapped to a complex modulation signal with a higher data bit width of 2 channels, in order to ensure that the constellation diagram The accuracy of the above coordinates, usually the data bit width of the complex modulation signal should reach 16 bits, that is, 3 bits must be enlarged to 2 channels of 16 bits, which is nearly 10 times larger, that is to say, the memory of the two channels of complex modulation signals The capacity is 10 times that of the custom data file, obviously, resulting in a great waste of resources

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