Oscillation Allowance = negative resistance (负性抵抗)
For optimum performance,an oscillator circuit must be designed in such a way as to enhance “negative resistance,” which is sometimes called the “oscillation allowance.”
【负性抵抗】Negative resistance (-R )
负性抵抗是振汤回路是否能持续稳定的振汤重要的参数,而negative resistance是一种判断振汤幅度品质的指标.如果振汤幅度的negative resistance不够好,幅度或许因为老化、温度、电压的改变而造成不会振汤.
这部份重点在於外在的回路杂散&X'TAL的负载电容的关系.因为X'TAL的负载电容值若是比较小,那PCB上回路所形成的杂散电容,会影响振汤频率机会则比较大,若规格上负载电容值是属於比较大,那杂散电容对振汤出来的频率影响会较小.