Specifications

UHP-1000 SATELLITE ROUTER

INSTALLATION AND OPERATION MANUAL, V. 2.5

(SW VERSION 2.5.X)

2.5.2 Searching the satellite carrier

Any LNB features LO frequency deviation from its declared value. This deviation has a certain constant component

plus component caused by temperature changes. Constant component may vary slowly due to LNB components

aging. Deviation due to temperature (winter/summer) usually lies within the bandwidth of ±500 KHz. Constant

component is usually not in excess of 500 KHz to either side but there are samples with deviation of up to 1,500

KHz. PLL LNB with 10 MHz internal reference fall also under this effect but their deviation range is substantially

lower – just a few KHz. Accuracy of PLL LNB with external reference frequency depends on the accuracy of the

router reference oscillator.

The LO inaccuracy leads to the fact that the real frequency of the carrier coming to the router differs from that at

which we expect this carrier.

Respectively, the router should search for the carrier in a certain bandwidth close to the selected value. The search

algorithm is as follows:

Figure 15 Satellite carrier search algorithm

Search is carried out within a certain user-defined bandwidth. If the carrier is not found upon reaching the search

limit the search is repeated. Search bandwidth should be wider than the possible frequency offset caused by

deviation in LO LNB. But the wider the range the longer is the complete search cycle.

2.5.3 SCPC demodulator control commands

Most commands of the demodulator come into force as the carrier search operation is initiated. If the search is

already under way the values come into force immediately. The essence of this behavior is that if demodulator

receives the carrier the user gets maximum possibilities to configure the demodulator without interrupting the

reception. This is particularly actual for a remote configuration.

demod lnb power on|off - LNB power control

Switching LNB power supply on and off. Comes into force immediately.

demod search 0-200000 - Carrier search bandwidth (+/-KHz)

Maximum deviation from the assigned frequency during carrier search. Full search bandwidth (to

both sides) is equal to the double value. If the command is issued with the 0 value, the bandwidth

does not change, and the LNB offset value is reset to 0. When values 1-4 are entered demodulator

works with constant frequency without any scans – it can improve lock time in mobile applications.

demod reference off|on - TDMA RX connector 10 MHz output

Activation of 10 MHz reference signal on TDMA Rx input.

The router demodulator is provided with two sets of carrier settings referred to as profiles A and B. Both profiles

are needed when there is a necessity to shift to a new carrier while working on the former and without deleting

settings of the former (so as to be able to go back if necessary).

START

END

F(base)

F(base)-Search_BW

F(base)+Search_BW

New search circle

FREQUENCY OF DEMODULATOR