Standard Communications mt930b, Руководство по обслуживанию, Страница: 7 / 155

MT930B Service Manual Page 1-1
CHAPTER 1
GENERAL INFORMATION
SCOPE
This manual is offered to Standard Communications Corp. (SCC) service dealers
to provide detailed service information for the indicated equipment. This
information includes service diagrams, parts lists and printed circuit board
layouts.
DESCRIPTION
The MT930B Satellite Receiver is an international, multi-standard, broadcast
quality 950 to 2150 MHz PLL-synthesised satellite receiver.
These units feature digitally locked, continuous-tuning AFC and
microprocessor controls. The C-band and Ku-band 950 to 2150 MHz radio
frequency (RF) inputs are dual-converted to a commercial, industrial-standard 70
MHz intermediate frequency (IF).
The MT930 Satellite Receiver design uses a new 70 MHz IF conversion circuit
that enables direct satellite processing of signal at the up/downlink site. This
circuit also provides more consistent video to the demodulator because it does
not require that the signal be processed to the baseband.
The front panel design incorporates a three-function meter that displays signal
strength, fine-tune, and carrier-to-noise (C/N).
The real-time C/N meter and alarm features consistently monitor the receiver
signals with maximum power ability. The tune meter enables precise fine-tuning
of the receive signal, and the signal meter is calibrated like a spectrum analyzer,
in dBm units.
Multiple video low-pass filters and de-emphasis networks enable the MT930B
Satellite Receiver for NTSC, PAL, SECAM, and MAC operation, along with all
known video scrambling formats. The multi-tap power supply with two voltage
settings decreases heat and power consumption, and is designed for 24-hour-a-
day operation.
FEATURES
What follows is a long list of tailored features.
•
Operation, performance, and features are specifically designed for the
professional broadcaster
•
PLL control of RF center frequency and audio sub-carriers