JPS6416004A - Signal generator - Google Patents

Abstract

PURPOSE:To prevent the fluctuation in the output level of a sinusoidal wave signal by supplying an SCF clock of the same frequency and same phase as those of an input clock given to generate a reference pulse signal to a switched capacitor filter. CONSTITUTION:An output I of an operational amplifier 11 passes through a low-pass filter 52 comprising the switched capacitor filter (SCF) 12. An output Y from a 1/l frequency divider 3 is given to an SCF clock generating circuit 13 and the SCF clock J from the SCF clock generating circuit 13 is fed to the SCF 12. The SCF clock J and the output Y are outputted from one and same 1/l frequency divider 3 and the input clock to the signal generator reference pulse generator 50 and the SCF clock have the same frequency. Thus, the pulse width of waveforms V, W is an integral number of multiple of the SCF clock J and each voltage change point of the output I to the SCF 12 and the SCF clock J have the entirely same phase relation. Thus, the input clock to the SCF 12 and the SCF clock have always the same phase.