| 摘要 |
PURPOSE:To measure frequency without complexing a circuit by converting an input signal into an intermediate frequency signal, counting up signals from a local oscillator for frequency conversion and low frequency signals after conversion or signals of a replacing oscillator and then totalizing these counted values by an arithmetic circuit. CONSTITUTION:After passed through the 1st frequency converting circuit 32, the 2nd frequency converting circuit 35 and the 2nd intermediate frequency circuit 37, a part of input signals from an input terminal 31 are inputted to a monitor output terminal 40 and the remaining signals are inputted to one input terminal of a switching circuit 43 through an oscillating circuit 41. Outputs from the switching circuit 43 are inputted to an arithmetic circuit 47 together with the outputs of the 1st local oscillator and the 2nd local oscillator through counting circuits 44-46 respectively and these inputted signals are electrically totalized by the circuit 47 and displayed by a display circuit 48. In case of a signal having many frequency components such as a modulated wave signal, the output is stabilized by actuating a replacing oscillator 41 to measure the output. Consequently the circuit configuration is prevented from complicat due to the duplication of the frequency converting circuit and measuring errors due to signal leakage. |
