Pulse width modulation (PWM) is widely used in different applications. PWM transforms the information in the amplitude of a bounded input signal into the pulse width output signal without suffering from quantization noise. The frequency of the output signal is usually constant. In this paper, the new PWM system with frequency changing (PWMFM) is described. In such PWMFM the pulse width and also the carrier frequency are changed. Therefore, two independent pieces of information can be simultaneously transmitted over one channel; hence PWM and frequency modulation (FM) are simultaneously used. But such system needs 2 demodulators, one for PWM and the second for FM. PWMFM can be used in the following applications: LED light intensity control via PWM and several LED block switching by FM PWMFM is highly useful in motor speed control applications by PWM and direction of rotation with FM. PWMFM can be used also in a class-D audio amplifier for power control, e.g. coarse by means of FM and fine by PWM. PWMFM can be used for the simultaneous transmission of two independent information between all, mutual combinations of analog and digital circuits. The analog and digital circuits for modulation and demodulation of PWMF signal are described and measuring results are presented in this work.

脉冲宽度调制（PWM）广泛用于不同的应用中。PWM将有界输入信号幅度的信息转换为脉冲宽度输出信号，而不会受到量化噪声的影响。输出信号的频率通常是恒定的。本文介绍了一种新型的具有频率变化的PWM系统（PWMFM）。在这种PWMFM中，脉冲宽度以及载波频率都被改变。因此，可以在一个信道上同时发送两个独立的信息。因此，PWM和调频（FM）同时使用。但是这种系统需要2个解调器，一个用于PWM，第二个用于FM。PWMFM可用于以下应用：通过PWM进行LED光强度控制以及通过FM进行多个LED块切换PWMFM在通过PWM和FM旋转方向进行电机速度控制应用中非常有用。PWMFM也可以在D类音频放大器中用于功率控制，例如，通过FM粗调和通过PWM精调。PWMFM可用于在模拟电路和数字电路的所有相互组合之间同时传输两个独立的信息。描述了用于PWMF信号调制和解调的模拟和数字电路，并给出了测量结果。模拟和数字电路的相互组合。描述了用于PWMF信号调制和解调的模拟和数字电路，并给出了测量结果。模拟和数字电路的相互组合。描述了用于PWMF信号调制和解调的模拟和数字电路，并给出了测量结果。