The .000001% of use cases for a simple passive VGA to HDMI is for when the video source is designed especially to output both VGA and HDMI. In these cases the cable will accompany the video source when you buy it. This is so rare, I almost regret writing this much about it. Analog vs Digital.
Definition - What does Pulse Width Modulation (PWM) mean? Pulse-width modulation (PWM) is a modulation process or technique used in most communication systems for encoding the amplitude of a signal right into a pulse width or duration of another signal, usually a carrier signal, for transmission.
pulse code modulation (PCM) Pulse code modulation (PCM) is a digital scheme for transmitting analog data. The signals in PCM are binary; that is, there are only two possible states, represented by logic 1 (high) and logic 0 (low). This is true no matter how complex the analog waveform happens to be.