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BPSK (Binary Phase Shift Keying) subcarrier related demodulation bit boundary determination circuit and method

A subcarrier and boundary technology, applied in the field of digital correlation demodulation circuit, can solve problems such as uncertainty, and achieve the effect of improving the success rate and simplifying the design

Active Publication Date: 2015-06-10
SHANGHAI HUAHONG INTEGRATED CIRCUIT
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, when performing digital correlation demodulation on the BPSK subcarrier at the 847k baud rate, if the high or low flip of the first flip cannot be accurately obtained, it will be impossible to determine whether to use the rising edge of the reference subcarrier during demodulation. It is still the moment of the falling edge to judge the relevant results

Method used

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  • BPSK (Binary Phase Shift Keying) subcarrier related demodulation bit boundary determination circuit and method
  • BPSK (Binary Phase Shift Keying) subcarrier related demodulation bit boundary determination circuit and method
  • BPSK (Binary Phase Shift Keying) subcarrier related demodulation bit boundary determination circuit and method

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Embodiment Construction

[0028] see figure 2 As shown, in the following embodiments, the BPSK subcarrier-related demodulation bit boundary determination circuit includes: a BPSK subcarrier rising edge counter, a first comparison module, a BPSK subcarrier high level statistical counter, a The second comparison module, a BPSK subcarrier high-low level counter, and a first flip bit boundary signal generation module. The BPSK subcarrier refers to the BPSK subcarrier at the 847k baud rate specified in the ISO / IEC14443 protocol.

[0029] The BPSK subcarrier rising edge counter counts the rising edges of the input BPSK subcarrier, and is used to count the number of BPSK subcarrier signals after the analog receiving circuit is turned on during the bit synchronization period.

[0030] The first comparison module compares the count value of the BPSK subcarrier rising edge counter with a set count threshold to generate a count enable signal, and when the count value of the BPSK subcarrier rising edge counter i...

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Abstract

The invention discloses a BPSK (Binary Phase Shift Keying) subcarrier related demodulation bit boundary determination circuit. The BPSK subcarrier related demodulation bit boundary determination circuit comprises a BPSK subcarrier rising edge counter, a first comparison module, a BPSK subcarrier high level counting counter, a second comparison module, a BPSK subcarrier high-low level counter and a first flipping bit boundary signal generating module. The invention further discloses a BPSK subcarrier related demodulation bit boundary determination method. The method comprises the following steps: counting the high and low levels of single-period BPSK subcarriers in a bit synchronization period respectively; after the completion of counting, taking statistical average values as the calculation reference values of the high and low levels of the single-period subcarriers in the bit synchronizing period; adding the calculation reference values of the high and low levels with high and low flipping offsets to obtain a first high flipping threshold value and a low flipping threshold value; and comparing the high and low level statistical values of the BPSK subcarriers with the high and low flipping threshold values to obtain a bit boundary locking signal and a bit boundary marking signal. Through adoption of the circuit and method, the success rate of first flipping point detection can be increased.

Description

technical field [0001] The invention relates to the field of digital correlation demodulation circuits, in particular to a BPSK (Binary Phase Shift Keying) subcarrier correlation demodulation bit boundary determination circuit under the 847k baud rate specified in the ISO / IEC14443 protocol. The invention also relates to a method for determining the BPSK subcarrier-related demodulation bit boundary. Background technique [0002] According to the BPSK code stream stipulated in the ISO / IEC14443 protocol (hereinafter referred to as the "protocol"), at a baud rate of 847k, each subcarrier represents a bit period. [0003] According to the agreement, whether it is typeA (type A) or typeB (type B) card returns BPSK code, there is a certain bit synchronization period, and there will be no phase inversion during the synchronization period, so according to the bit synchronization period to be demodulated The rising edge of the carrier is detected, and a reasonable rising edge can be ...

Claims

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Application Information

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IPC IPC(8): H04L27/22
CPCH04L27/2278
Inventor 王永流
Owner SHANGHAI HUAHONG INTEGRATED CIRCUIT