JVC NAB-2007 Fig. 7. , MICROWAVE WIRELESS

JVC Professional APRIL 2007 NAB-2007 The ProHD Report

Fig. 7. You just saved $30,000 again (typical HD encoder cost for the

ENG Van) by using the built-in HD Super Encoder in the ProHD

camcorder. The highly cost effective BMS camera-back TX unit does

not include a (expensive) built-in HD encoder, as it takes in the

compressed 20Mbps HD stream from the camcorder. Easy microwave!

The BMS Microwave Camera-back unit accepts the 1394 output from the

camcorder (MPEG-2 TS at 20Mbps), modulates 16-QAM and transmits COFDM in

the 2GHz microwave band (12MHz channel with the 8MHz pedestal and guard

bands) to the ENG Van, where a matching BMS Microwave Diversity Receiver

decodes the modulation and formats the MPEG-2 TS at 20Mbps to ASI output,

which is then supplied to your existing (or new) digital Eng Van-to-Studio

microwave transmitter’s ASI input. You have eliminated the need for that $30,000

HD encoder in the ENG Van, and your news master control receives a live,

broadcast quality full bandwidth 1280x720p60 native signal. Easy microwave!

What about CODEC latency? The ProHD MPEG-2 Super Encoder compresses the

1280x720p60 using a GOP of 12, which GOP section equals 1/5th of a second or

200mS (12 frames of total 60 frames in a second). Other manufacturers employing

HDV in 1080i60 (30 frames) use GOP of 15, which GOP section equals ½ of a

second or 500mS (15 frames of total 30 frames in a second). Total encode/decode

latency for ProHD is marginally more than 400mS, quite acceptable in HD ENG

even in live remote interviews, while the HDV 1080i60's encode/decode latency

of more than one second may be problematic.

IEEE-1394

(MPEG-2 TS

20Mbps) Microwave TX

& Modulator

JVC GY

HD250U

ASI Input

ASI Output

ProHD Microwave

Camera-back TX

BMS

Diversity Whip Antennas

BMS Microwave

Diversity RX

Diversity Whip

Antenna Inputs

MICROWAVE WIRELESS