A relation between electromagnetic noise from an LED light bulb and its impact on BER performance of the DTTB is estimated from the APD measurement. First, the APD of the noise is measured with various resolution bandwidths. The characteristic of the APD of the noise is similar to the Gaussian noise when the resolution bandwidth becomes narrow. Then, the BER performance of the DTTB subjected to the noise of the LED light bulb is estimated from the APD result with the resolution bandwidth that is nearly equal to the subcarrier band range of the DTTB. As a result, the BER of the estimated result agrees well with measured results which are subjected to the LED light bulb and the Gaussian noise. Therefore, the effect of the noise from the LED light bulb on the DTTB is similar to the effect of the Gaussian noise.