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A method and system for removing direct current

A technology to remove DC and frequency points, applied in transmission systems, electrical components, etc., can solve problems such as large delay, unfavorable implementation, and affecting receiver performance, and achieve good effect of removing DC with little impact

Active Publication Date: 2022-06-21
上海擎昆信息科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the ML estimation method has a high complexity and is not conducive to implementation; the average DC removal method has better performance for some systems, such as GSM systems, etc., but it is not suitable for some systems with broadband DC, and in order to accurately calculate the DC , will cause a large delay and affect the performance of the receiver

Method used

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  • A method and system for removing direct current
  • A method and system for removing direct current
  • A method and system for removing direct current

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] An embodiment of the present invention, such as figure 1 As shown, the present invention provides a method for removing direct current, comprising the steps of:

[0052] S1. When the receiver is in preliminary network search and the receiving frequency is the first frequency in the synchronization phase, configure the receiving frequency to be the second frequency for data reception.

[0053] Preferably, when the receiver is in a preliminary network search and the receiving frequency is the first frequency in the synchronization stage, the receiving frequency is configured to be the second frequency for receiving, which specifically includes:

[0054] S11. The receiver is in preliminary network search, and when the receiving frequency point in the synchronization stage is F0 (MHz), the receiving bandwidth is increased.

[0055] S12, configure the receiving frequency point to be (F0-f1) MHz for data reception, and f1 is a preset parameter.

[0056] S2. De-DC is perform...

Embodiment 2

[0068] An embodiment of the present invention, on the basis of Embodiment 1, uses a notch filter to remove DC from the received data, which specifically includes:

[0069] Set the DC suppression parameter of the notch filter to k, and remove the DC from the received data, where k=5, 6, 7, ... 12, the larger the k, the narrower the DC suppression bandwidth.

[0070] Specifically, the received data is de-DC by setting the DC suppression parameter k of the notch filter. In this embodiment, the value of k is 5, 6, 7, ... 12, a suppression bandwidth of 15Khz, and a maximum suppression of 20dB. Notch Filter spectrum as figure 2 As shown, when k is larger, the DC rejection bandwidth is narrower, and the rejection at 0 Hz is relatively weaker.

[0071] preferably, as image 3 and Figure 4 As shown, the average DC removal module performs DC removal, including: setting the input parameter as the period data_len, and calculating the DC usage data length as dc_len; for the input data...

Embodiment 3

[0073] In an embodiment of the present invention, on the basis of Embodiment 1 or 2, when the receiver is in a normal receiving state, the receiving frequency points are normally configured, the coordinate rotation digital calculation module is turned off, and the notch filter or average DC removal is enabled. The module is de-DC, including:

[0074] S41. When the receiver is in a normal receiving state, the receiving frequency points are normally configured, the coordinate rotation digital calculation module and the notch filter are turned off, and the average DC removal module is enabled.

[0075] S42 , normally receive the frequency domain data and perform signal processing, when the signal-to-noise ratio is greater than a preset value and the decoding is correct, reconstruct the frequency domain transmit signal.

[0076] S43. Calculate the noise energy of each subcarrier in the frequency domain by using the frequency domain transmission signal and the frequency domain chan...

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Abstract

The present invention provides a method and system for removing direct current. The method includes the steps of: when the receiver is in preliminary network search and the receiving frequency point is the first frequency in the synchronization stage, configure the receiving frequency point to be the second frequency for data reception; wave filter to the received data to remove the direct current; configure the rotation parameter of the coordinate rotation digital calculation module to be the difference between the first frequency and the second frequency, and receive data for synchronization; when the receiver is in a normal receiving state, the normal Configure the receiving frequency point, turn off the coordinate rotation digital calculation module, and enable the notch filter or the average DC removal module to remove DC. This solution can flexibly adjust the DC removal method according to the actual use scenario, so that the DC removal effect of the system is better, and the impact on the receiver is small.

Description

technical field [0001] The present invention relates to the technical field of receiver DC removal, in particular to a DC removal method and system. Background technique [0002] The zero-IF receiver is a receiver that can directly convert the radio frequency signal into the original transmission signal without going through the intermediate frequency. The zero-IF receiver has no image interference and is easy to achieve single-chip integration, so it is widely used. [0003] In a wireless communication system, the performance of a zero-IF receiver is often interfered with by DC, and DC will affect the performance of the receiver. Therefore, it is necessary to perform DC removal processing on the receiver. Existing solutions generally use methods such as averaging to remove DC, ML estimation to remove DC, etc. However, the ML estimation method of removing DC is more complicated, which is not conducive to implementation; the average DC removing method has better performance ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04B1/30H04B1/12
CPCH04B1/30H04B1/12
Inventor 谭定富唐兵武传国是元吉
Owner 上海擎昆信息科技有限公司