High linearity variable bit width interpolator

Abstract

The invention discloses a high linearity variable bit width interpolator, comprising two input reference phases Ain and Bin, a phase control word PIN (0:X), and an interface of a bit width control word PIN_len. The bit width of the input reference phases is changed by the phase width control word PIN (0:X) to regulate the output phase precision of the interpolator. As the invention brings in the enable logic to an interpolation unit (MixerCell), the interpolation unit (MixerCell) can be divorced from a main circuit at any time in the working condition to realize the changeability of the bit width of the input phase control word and flexibly change the interpolation output precision. Meanwhile, a controllable switch corresponding to the input phase control word is introduced on a leakage path of the interpolation unit (MixerCell), therefore crosstalk caused by difference between proper time of two pairs of reference differential signals of input ends of the interpolator is modified, and then the linearity of the interpolation output result is greatly improved.

Description

technical field [0001] The invention relates to the field of integrated circuits, in particular to a high linearity-variable bit width interpolator. Background technique [0002] High-linearity interpolators are widely used in data receiving-transmitting systems, such as data sampling, frequency jitter generation (including frequency ssc) and other functional modules. In the case of different digital configuration words, the linear interpolator generates uniform multi-phase clocks, and high-performance data receiving-transmitting systems require these clocks to have extremely high linearity and consistency. [0003] The interpolator works as figure 1 As shown, the input Ain and Bin homologous clocks are obtained through different delays respectively, and the phase difference is Φ, which is expressed as a time delay tDelay. The interpolator also has a phase control word input: PH<0:X>, the input control word controls the output signal phase of the interpolation unit, ...

AI Technical Summary

Problems solved by technology

If it is necessary to flexibly change the interpolation accuracy in some applications, more than two sets of hardware are required, and the reusability is poor

like figure 2 As shown, thus greatly limiting its scope of application

[0005] In addition, although the traditional interpolator can precisely control the symmetry and matching of the layout to eliminate the difference in space, the input signal is coupled to the output through the parasitic capacitance of the input tube in the high-speed state, such as image 3 As shown, the two signals at the input of the interpolator will cause crosstalk due to the difference in phase, that is, the difference in time, which will deteriorate the linearity of the interpolation output, making the phase change non-uniform, and the minimum value of the control word PH During the change from (0,...,0) to the maximum value (1,...,1), the front phase Ain cannot be completely switched to the back phase Bin when the interpolator outputs

[0006] Therefore, the input phase control word width of the traditional interpolator has no scalability and poor hardware reusability, which greatly limits its application range

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