Using 8253 and 8255 sent out the sound with fixed frequency.

并利用8253定时器和8255可编程控制器发出了指定频率的声音。

With fixed frequency control circuit, it provides with over voltage, over current, overheat and short circuit protection.

该系列电源适配器，采用固定频率控制电路，具备限流、限压、过温、短路全功能保护。

But Steady low fan speed change, so that airflow and vibration according to a fixed frequency, so we might as natural wind moderate.

但稳定低风扇速度变化，使气流和振动按固定频率，因此我们可能是自然风温和。

With the drastic frequency competition of communication, the usual communications with fixed frequency suffer from a serious threat.

随着通信领域的频率竞争愈演愈烈，惯用的定频通信受到了严重威胁。

The fixed frequency sample PWM method is put forward in this paper together with the theoretical analysis about their switch strategy.

本文提出恒频采样电流跟踪型PWM方式，并对其开关策略进行了理论分析。