HD, or High Definition car audio will give you much better sound quality from your favorite FM stations. The HD format is a digital signal that delivers much higher quality audio, plus programming information to your HD equipped car stereo. The terms HD and digital are interchangeable when you’re talking about FM radio stations. However, there is also satellite radio which is a completely different thing and will sometimes also require a different satellite receiving capable receiver. HD and digital can refer to the same type of radio signal, however, they usually refer to completely different systems.
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