窄带带通滤波
narrowband band-pass filter
脐带缠绕
Cord entanglement
Encirclement of umbilical cord
230MHz无线窄带数传
230 MHz wireless narrow band data transmission
超高频窄带信号
UHF signal in narrow-band
超窄带调制
UNB Ultra Narrow Band Modulation
Burderhedral
超窄带光谱
Ultra-narrow-bandwidth(UNB) spectrum