The following diagram shows a typical block diagram

for a twin universal LNB design. The ZLNB2012 device

provides the two polarity and two tone

switches

required to decode the two independent receiver

feeds. The device is also able to detect the absence of a

revceiver connection to either port of the LNB

providing all outputs to go high hence disabling of the

port. This allows the avoidance of unwanted signal

reflections from an unterminated down feed cable.

Additionally the front end bias requirements of the LNB

are provided by the ZNBG4000 or ZNBG6000 offering a

very efficient and cost effective solution

PROVISIONAL ISSUE A - OCTOBER 2001

5

ZLNB2012

Bias Generator

ZNBG40XX

Series

ZLNB2012 Series

Dual H/V Switch

&

22kHz Switch

Vertical

Antenna

Horizontal

Antenna

Gain Stage

GaAs/HEMTFET

Gain Stage

GaAs/HEMTFET

1

4

2

IF down feed

950-1750 MHz

- Standard Band

950-2050 MHz

- Enhanced Band

H/V Output 2

H/V Output 1

3

Control Input

<=13V-Horizontal

>=14.5V-Vertical

Control

High Band

Horizontal

Low Band

Horizontal

High Band

Vertical

Low Band

Vertical

PIN

Diode

MUX

DC Input

13-25V

ASTRA

10.95 GHz-11.7 GHz

Standard Band

10.7 GHz-11.8 GHz

Enhanced Band

+

+

Mixer

+

+

Mixer

Low Band

Low Band

High Band

High Band