If used with DTV converter boxes, these will need analog passthrough in order not to block incoming FM radio signals. A small number of TV receivers were also manufactured with built-in broadcast radio receivers these included some small portable devices or (more rarely) sets marketed for hotel/motel use.
In the US, this primarily affects low-power and broadcast translator stations, as these are exempt from the FCC mandate to switch to digital broadcasting in 2009, as well as foreign signals that will remain in analog form. With a box that lacks analog passthrough, no other signals are sent to the output, so all analog stations are lost.
Any converter box converts the digital signal for the current digital sub-channel to an analog signal (at the reduced screen resolution of the analog standard), outputs that signal onto analog channel 3 or 4 (set by the user to avoid any conflict with local over-the-air channels) and sends that signal to the analog tuner in the TV. Those with analog passthrough allow both digital and analog television to be viewed on older TVs.īefore digital television, passthrough originally existed in VCRs (and later PVRs and DVDRs) that connected to TV set using RF connector, allowing the TV antenna or cable TV signal to be switched to pass through the VCR, or have VCR output added as an extra channel.Īll digital-to-analog converter boxes have both an antenna input (which accepts the coaxial cable that formerly went directly to the TV) and an RF output (which now goes directly to the TV). Boxes without analog passthrough only allow digital TV ( ATSC standard) to be viewed on older, analog-only ( NTSC standard) TVs.
( Learn how and when to remove this template message)Īnalog passthrough is a feature found on some digital-to-analog television converter boxes.
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