填空题 The basic period of the signal $x(n)=A\cos(\frac{3\pi}{7}n+\frac{\pi}{6})$ is ____.

填空题 The basic period of the signal $$x(n)=e^{j(\frac{2\pi}(____)n+\frac{\pi}{5})}$$ is ____.

填空题 The system $$y(n)=x(n)+2$$ is ______ (linear or nonlinear), ______ (time-invariant or time-varying).

填空题 If $$1+i$$ is the zero point of system transfer function H(z) for Linear phase FIR, ______ ______ are also zeros of Linear phase FIR.

填空题 The system $$y(n)=4x(n)+3$$ is ______ (linear or nonlinear), ______ (time-invariant or time-varying).

填空题 The Z-Transform of the sequence $$\delta(n)+3\delta(n-2)+\delta(n+1)$$ is __________, it’s ROC is ______.

填空题 The basic period of the signal $$x(n)=e^{j\frac{2\pi}(____)n}$$ is ____.

填空题 The system $$y(n)=(\frac{1}{2})^{n}u(n)$$ is ____ (causal or noncausal), ______ (stable or unstable).

填空题 The system $$y(n)=(\frac{1}{2})^{n}u(n)$$ is ____ (causal or noncausal), ______ (stable or unstable).