Development of OFDM OBL Prototype System for HDTV Mobile Relay Broadcasting


Transmitter(front left),
Receiver(front right),
receiving antenna(rear left)
and receiving header(rear right)
The STRL constructed a prototype OFDM OBL(Outside Broadcasting Links) system designed for Hi-Vision (HDTV) broadcasting from road races including both marathons and long distance relay races.
The OBL currently used at road races transmits mainly on the 800MHz-band. Although the intensity of radio waves on this band fluctuates significantly during mobile relays, the OFDM scheme is capable of stable video transmission even during radio fluctuations. The OFDM OBL used for standard TV is already in active service and has proven its effectiveness.
This newly developed experimental system utilizes the 18MHz-band to secure the necessary transmission capacity for HDTV programs. It can also use a variety of modulation and error correction schemes. In order to realize stable transmission and reception, we also adopted a new subband-division diversity reception scheme, which performs the optimum composition from signals received at three antennas.
We will conduct further experiments at an actual relay race course using various schemes, to contribute to the practical implementation of the system.


Exhibition of New Super-HARP Handheld Camera at NAB2001


New Super-HARP handheld camera
The broadcasting-related equipment exhibition, NAB2001, sponsored by the NAB (National Association of Broadcasters), was held in Las Vegas from April 23, 2001. A handheld camera for standard TV equipped with the "New Super-HARP," an ultrahigh sensitivity image tube developed at the STRL, was exhibited .
This camera has high sensitivity, approximately 50 times greater than that of a CCD camera, which enables nighttime shooting with good video quality. At the exhibition site, we performed a demonstration in which the camera shot a subject on a set so dark that the subject could hardly be seen with the naked eye (lighting was less than 1 lux), yet the camera reproduced a clear image of the subject.