North Korea appears to be testing digital radio broadcasting.

Hiroshi Inoue, a radio monitor in Japan, received on Wednesday the country’s international radio service, Voice of Korea, broadcasting on shortwave using DRM (Digital Radio Mondiale). DRM is a digital broadcasting technology developed for use on AM and shortwave services.

He posted a couple of clips of the on YouTube. While reception isn’t perfect, the audio identification of Voice of Korea can clearly be heard.

The broadcasts are taking place on 3,560MHz, a frequency used by the Voice of Korea in the past for conventional analog shortwave broadcasts.

In a blog posting Mr. Inoue says he heard broadcasts in several languages including English, Arabic and French. Relays of domestic KCBS broadcasts were also heard.

The tests appear to be taking place with assistance from Chinese engineers. The DRM identification used in data stream, visible in the YouTube clip, is CUC-ECDAV. That’s almost certainly the Radio and Television Engineering Research Center (ECDAV) at the Communication University of China (CUC): http://ecdav.cuc.edu.cn . The university lists DRM as one of the areas in which it is carrying out research.

Another hint to Chinese involvement can be seen in the program type identification, which incorrectly shows “Chinese (Mandarin) Pop Music.”

North Korea’s testing of DRM comes at a time when the country appears to be upgrading its international radio broadcasting system.

In mid-June 2011 the country’s Ministry of Posts and Telecommunications signed a deal with Beijing-based BBEF Tech for several new radio and television transmitters. The Chinese company trained North Korean engineers in how to install them.

At least one of those transmitters now appears to be on the air. North Korea’s transmissions on 11,680kHz shortwave are now broadcast spot-on that frequency. In the past they drifted a little either side of the correct channel.

(Thanks to DX Aktuell for the tip!)