数字电视接收机同步时间估测方法

Method for measuring recovery time of digital television receiver

数字电视接收机同步时间是数字电视服务质量的一项重要指标,但同步时间在现有设备条件下不能直接测量得到.为此使用误码测试仪和脉冲噪声源设备,通过多次测试脉冲噪声造成的误码秒的个数,计算得出数字电视接收机同步时间.由于采用随机时刻触发的方式,修正了原方法中与起始时刻相关的局限性;由于对脉冲噪声的长度没有限制,可用于测试更长交织时间的系统的同步时间;测量精度达到0.1 s,与直接测量方法相比提高一个数量级.此方法经过数学推导验证,并通过数字电视地面广播标准接收机的实测数据讨论了测量参数对同步时间的影响.

Recovery time of digital television（DTV） receiver is an important indicator of DTV service quality but the recovery time can not be measured directly with existing equipments.A new method was presented which measure the recovery time by bit error rate（BER） tester and impulse noise source through a series of the errored seconds caused by impulse noise.Different from the traditional way,a random trigger of pulses was used in this method,which resulted that the estimation of recovery time was not associated with the pulse＇s start time.Without limit of the impulse noise length,the method can be used for measuring recovery time of the longer time-interleaver transmission systems.The recovery time measured in this method is with a precision of 0.1s,which is an order of magnitude lower than past experiments.The effect of experimental parameters on recovery time was analyzed with the test result in a digital terrestrial multimedia broadcasting（DTMB） receiver.