Question about EPWM sample project in starterware

dear TI members,

i just bought TI LCDK C6748 dev kit and just beginning to develop using TI DSP IC..

i load it with Starterware example project of EHRPWM..

i successfully build the project and make some modification with the Action qualifier register as below :

EHRPWMConfigureAQActionOnA(SOC_EHRPWM_1_REGS, EHRPWM_AQCTLA_ZRO_EPWMXAHIGH, EHRPWM_AQCTLA_PRD_DONOTHING,
EHRPWM_AQCTLA_CAU_EPWMXALOW, EHRPWM_AQCTLA_CAD_DONOTHING, EHRPWM_AQCTLA_CBU_DONOTHING,
EHRPWM_AQCTLA_CBD_DONOTHING, EHRPWM_AQSFRC_ACTSFA_DONOTHING);

it is successfully load and generate the PWM signal at EPWM1A pin..

i expect the resulted signal will be 1 full square wave in every period of PWM..

but the resulted signal is consisted of many square wave within 1 period of PWM signal as below picture..

is it normal that 1 period of PWM signal consisted as many square wave signal?

how can i make 1 full square wave signal every period of PWM?

thank you

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