23 Nov DRM was designed with the needs of a single broadcaster per transmission in mind – Your Questions Answered
Our best specialists will respond in brief to your questions. We will post them regularly. Please submit them in writing and in audio with your picture and we will post the answers here. Please keep your questions short and relevant and send them to: projectoffice@drm.
23rd November 2002
Why do you say that in DRM you can have up to 3 programmes on one Am or FM current frequency? With better compression could there be more than three programmes? What is the parameter which is restricting it to the three programs only? [Sandeep Srivastava]
DRM was designed with the needs of a single broadcaster per transmission in mind. The theoretical maximum per transmission is 4 services, with a maximum of 3 of them being audio services along with value components and pure data services. The major reason for limiting the number of audio services is the available bandwidth. On the AM bands, even with least robustness and maximum capacity at double channel configuration, we are looking at 72 kbps – less than 24 kbps per audio service (if we want to keep some capacity for Journaline text and service logos). In the FM bands, the theoretical maximum capacity under similar conditions is 186 kbps – leaving close to 60 kbps for each audio service. However, in both scenarios, a broadcaster would in most cases rather decide to go for a more robust transmission (i.e. better coverage in critical locations, and/or reduced transmission power), leaving significantly less capacity for audio content in those cases.