A device and method for measuring phase noise of a pulse modulation signal

Abstract

The present invention proposes a pulse modulation signal phase noise measurement device, which includes a down-conversion and quadrature phase detection operation unit. The down-conversion and quadrature phase detection operation unit includes: a down-conversion unit, a positive Intersection phase detection unit and sampling operation unit; the down-conversion unit includes: a local oscillator, a frequency mixer, an adjustable band-pass filter and a low-noise amplification unit; the quadrature phase detection unit includes a phase detector, a low pass filter, secondary low-noise amplification unit, loop filter and reference source; the sampling operation unit includes an A / D sampling unit and an analysis operation unit, and the output signal of the quadrature phase detection unit is sampled by A / D The phase noise measurement results are obtained after the unit and the analysis operation unit. The invention reduces the quantity of required testing instruments and cables, simplifies the measurement steps and reduces the difficulty of testing.

Description

technical field [0001] The invention relates to the technical field of testing, in particular to a pulse modulation signal phase noise measurement device, and also to a pulse modulation signal phase noise measurement method. Background technique [0002] Phase noise is an important indicator for evaluating the short-term stability of signal frequency. The performance of phase noise has an important impact on the overall performance of electronic systems, such as the range of radar systems, target resolution, bit error rate of digital communication systems, and image signals. Indexes such as quality, satellite positioning accuracy, and signal interference between adjacent channels of the receiver system are all related to the carrier phase noise of the system frequency source. [0003] Because pulse modulation signals have strong communication security and anti-interference performance, they have been widely used in secure communication systems and radar equipment. Most of th...

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Problems solved by technology

If this voltage cannot be eliminated, the back-end amplifier will quickly enter a saturated state, resulting in a decrease in system sensitivity

When the reference source is continuous wave, all the amplitude modulation noise of the local oscillator signal will be transferred to the IF port, and only part of the phase noise will be transferred. Although the amplitude modulation noise of the reference source is usually much lower than the phase noise, as The reduction of the duty cycle of the pulse modulation signal, the two will gradually approach and eventually affect the measurement of phase noise

In order to eliminate the unfavorable factors brought by the continuous wave phase detection to the phase noise measurement, the pulse reference source is usually used as the local oscillator, which can effectively suppress the deterioration of the DC offset and amplitude modulation noise, but it still needs to solve the problem between the measured signal and the reference source. pulse synchronization problem

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