FM radio is typically tuned using a superheterodyne receiver. This type of receiver contains two main sections. First the signal from the antenna is amplified, filtered and translated down to a fixed intermediate frequency. The second part of this receiver provides further filtering and demodulates this fixed intermediate frequency signal.[2][3] In order to change stations the front end of the superhetrodyne receiver is retuned to a new frequency. This translates a different station onto
the same fixed intermediate frequency which is then processed exactly the same way as any other station would be. In order to gather RDS information from all tunable stations an analog system would need to do one of the following: retune very rapidly, sequentially update stations waiting for at least 5 seconds on each station, or contain numerous superheterodyne receivers. The RDS data changes every 0.84 milliseconds (ms). This means that the receiver system must be tuned to every station we are interested in within less than a millisecond. Some commercially available analog FM receivers have a seek/tune time as high as 60ms and thus cannot accomplish this timing requirement.[4] Waiting for the 5 seconds to collect all the RDS data before it repeats could work well for 2-3 stations where the station data is updated only
every 10-15 seconds. However, it is common to have over 10 tunable stations in a given location. This introduces refresh times approaching one minute which no longer has the desired effect of being real time. Multiple parallel FM receivers
could be used. This would require much more hardware as well as create a potential restriction on the number of stations that could be processed at one time.