quad

1.500和600系显示器通过四线，多路器，数录像机生成更大的多屏图像，并能提供更多的图像细节。

The 500 and 600 series displays provide bigger multiscreen images from quads, multiplexers, and digital video recorders, providing more image detail.

2.A decade or so ago, I designed a simple circuit that included a quad optoisolator arranged in a full-wave analog-multiplier bridge (Figure 1).

大约十年前，我设计了一个简单电路，包括按全波模拟乘法器电的四个光耦（图1）。