Micro Digital Satellite Receiver Manual de usuario descargar pdf (Pagina 5)

AN2677/D

DiSEqC Introduction

Digital Satellite Equipment Control (DiSEqC ) using MC68HC908QT/QY 5

Figure 2. Functional Block Diagram

The MC68HC908QT4 MCU receives the DiSEqC control message, decodes it,

and controls the RF PIN-diode switch.

The DiSEqC switch unit (DSU) controlled by the MC68HC908QT4 MCU allows

both DiSEqC and non-DiSEqC control signals from the satellite receiver to be

used.

The satellite receiver sends the control message to the LNB switch in

accordance to DiSEqC standard level 1.0 (see References). The LNB switch

switches between LNB-A or LNB-B. The supply voltages and the 22-kHz signal

are produced by the IDU (satellite receiver). The capabilities of this control unit

with the MC68HC908QT4 can be expanded to a maximum of four LNBs

(LNB-A, -B, -C, and -D) in accordance with DiSEqC level 1.0 control standard.

DiSEqC Slave

Modes

The DSU (DiSEqC switch unit) works in two main modes, based on the type of

control:

– Non DiSEqC control — voltage/frequency/burst control (VFC)

– DiSEqC control

Non-DiSEqC Control

(VFC Mode)

In VFC mode, the DSU is not sensitive to voltage changes (+13 V or +18 V) or

the presence of the 22-kHz signal.

The signal (voltage and 22-kHz tone) is generated by the satellite receiver to

switch the target LNB between H/V polarizations, and between the low and high

bands received (22 kHz absent/present). The DSU is through-hold for this

signal.

SAT A

IF OUT

(2)

SAT B

22-kHz

NETWORK

CONTROL CIRCUIT

WITH MC68HC908QTY MCU

(1)

SWITCH

(3)

(4)

COAX. CABLE

NOTES:

I/O FROM SATELLITE LNB (IF 950 MHz TO 2150 MHz, dc SUPPLY, 22 kHz SIGNAL)

MODULATED DiSEqC DATA

CONTROL SIGNALS FROM MCU

COAX. CABLE BETWEEN ODU AND RECEIVER

(dc SUPPLY 20 V, DiSEqC DATA, IF BAND TO RECEIVER)

ODU

Freescale Semiconductor, I

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

1 2 3 4 5 6 7 8 9 10 11 12

Freescale Semiconductor, I 1

Comentarios a estos manuales

Sin comentarios

Micro Digital Satellite Receiver Manual de usuario Pagina 5

Comentarios a estos manuales

Relacionado con productos y manuales para Receptor Micro Digital Satellite Receiver