Delay line oscillator is composed of broadband amprifer adjustable attenuator and saw sensor device . after output signal of delay line oscillator is smoothed , it mixes with 109mhz local oscillation signal . its differential frequency signal is smoothed by low - pass filter trimmed by shaping circuit and processed by digital processing circuit 延遲線振蕩器由寬帶放大器、可調衰減器和聲表面波質量傳感器件構成。延遲線振蕩器輸出信號經濾波后與109mhz的本機晶體振蕩器輸出信號相混頻,通過低通濾波取其差頻,并經整形后由數字信號處理電路處理。