Bird Technologies Group 6138X Manual De Usuario
TX RX Systems Inc. Manual 7-9485-1.9.1 10/26/17 Page 8
tions for the 6138X family of channelized signal
boosters are listed in Table 2.
boosters are listed in Table 2.
Down / Up Conversion
A channelized signal booster has much in common
with a superheterodyne (superhet) receiver. The
incoming signal is converted to a lower frequency
so that single channel selectivity can be obtained.
It is then filtered. Unlike the superhet receiver how-
ever, the signal is not demodulated. Instead, it is
up-converted back to its original frequency where it
is further amplified to reach a useful power level.
with a superheterodyne (superhet) receiver. The
incoming signal is converted to a lower frequency
so that single channel selectivity can be obtained.
It is then filtered. Unlike the superhet receiver how-
ever, the signal is not demodulated. Instead, it is
up-converted back to its original frequency where it
is further amplified to reach a useful power level.
Figure 1 shows a simplified block diagram that
illustrates the down/up conversion principle. An
incoming signal at (Freq IN) is amplified and
applied to the first mixer along with a signal from a
local oscillator (Freq LO). A third signal at an inter-
mediate frequency (Freq IF) is produced as a result
of the mixing. The intermediate frequency is given
by the following relationship:
illustrates the down/up conversion principle. An
incoming signal at (Freq IN) is amplified and
applied to the first mixer along with a signal from a
local oscillator (Freq LO). A third signal at an inter-
mediate frequency (Freq IF) is produced as a result
of the mixing. The intermediate frequency is given
by the following relationship:
(1) Freq IF = Freq IN - Freq LO
The IF signal from the mixer then passes through
digital filtering with single channel bandwidth
before being amplified and passed on to the sec-
ond mixer. The second mixer also receives the
same local oscillator signal (Freq LO). The result is
a mixing product frequency at the output of mixer 2.
The output frequency (Freq OUT) is given by the
following relationship:
digital filtering with single channel bandwidth
before being amplified and passed on to the sec-
ond mixer. The second mixer also receives the
same local oscillator signal (Freq LO). The result is
a mixing product frequency at the output of mixer 2.
The output frequency (Freq OUT) is given by the
following relationship:
(2) Freq OUT = Freq IF + Freq LO
Substituting equation (1) for the “Freq IF” term in
equation (2) allows the “Freq LO” terms to be can-
celed yielding:
equation (2) allows the “Freq LO” terms to be can-
celed yielding:
(3) Freq Out = Freq IN
Frequency Range (MHz)
763 - 775 and 793 - 805 (units sold in USA)
806 - 824 and 851 - 869 (units sold in USA)
806 - 824 and 851 - 869 (units sold in USA)
764 - 776 and 794 - 806 (units sold in Canada)
806 - 824 and 851 - 869 (units sold in Canada)
806 - 824 and 851 - 869 (units sold in Canada)
Number of Carriers per Module
Low Density Model
High Density Model
14 uplink and downlink
30 uplink and downlink
30 uplink and downlink
Gain
Low Power Version
High Power Version
80 dB (min)
95 dB (min)
95 dB (min)
Maximum RF Bandwidth
700 MHz module
800 MHz module
800 MHz module
12 MHz
15 MHz
15 MHz
Output Level
Low Power
High Power
-30 to 10 dBm composite
-15 to 32 dBm composite
-15 to 32 dBm composite
Maximum Continuous Input Level
Operational: -20 dBm
Static w/o damage: -10dBm
RF In/Out Impedance
50 Ohms
Alarms
Form-C Contacts
Power
90 - 250 VAC, 50/60 Hz
or
- 48 VDC
Operating Temperature Range
-30°C to +60°C
95% RH (non-condensing)
Table 2: Specifications.