The KH3939 from Beijing KeHuan Century EMC Technology is a EMI Receiver with Attenuation 35 to 40 dB, Frequency 9 kHz to 300 MHz, Measurement Range 0 to 120 dBuV, Resolution 30 Hz to 10 kHz, Supply Voltage 220 VAC. More details for KH3939 can be seen below.