Adjustable jitter measurement circuit based on self-reference signal

Abstract

The invention discloses an adjustable jitter measurement circuit based on a self-reference signal; an output end of a single-period collecting module is electrically connected with input ends of a first alternative data selector MUX1 and a second first alternative data selector MUX2; the output end of the first alternative data selector MUX1 is electrically connected with an input end of a first oscillating loop; the second alternative data selector MUX2 is electrically connected with the input end of a second oscillating loop; the output ends of the first oscillating loop and the second oscillating loop are both electrically connected with the input ends of phase discriminator; the output end of the phase discriminator is electrically connected with a reset signal generating module; and a counter is electrically connected with the second oscillating loop. The adjustable jitter measurement circuit based on self-reference signal, overcoming the disadvantages of low measurement accuracy, difficult correction, limited measurement scope, low resolution and low measurement speed in the prior art, has advantages of high measurement accuracy, convenient correction, wide measurement scope, high resolution and high measurement speed.

Description

technical field [0001] The invention relates to the field of electronic circuits, in particular to a calibratable jitter measurement circuit based on a self-reference signal. Background technique [0002] With the continuous progress of microelectronics technology and the continuous improvement of integrated circuit performance, the development of high-speed communication systems is getting faster and faster, and the requirements for clock frequency of high-speed communication system chips are also getting higher and higher. Phase Locked Loops (PLL for short) is one of the more commonly used clock generators at present. Clock jitter is an important parameter of PLL. The size of clock jitter in high-speed communication systems must be within the range specified by the design specification. Otherwise, it will lead to a series of problems such as system performance degradation, so the jitter measurement method is also more important. [0003] Currently, as shown in Figure 1(a)...

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Problems solved by technology

[0008] (1) Poor measurement accuracy: Due to the existence of process deviation, the delay time of each delay unit in Figure 1(a) cannot be controlled to be equal, thus affecting the accuracy of measurement;

[0009] (2) Difficulty in calibration: the circuit contains multiple sets of delay units, and it is not easy to achieve calibration;

[0010] (3) The measurement range is limited: when measuring signal jitter, it is necessary to input an ideal signal as a reference clock, which affects the measurement range;

[0011] (4) Low resolution and slow measurement speed: a large number of counters and phase detectors are used in the circuit, and the circuit area is large, which affects the resolution and measurement speed

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