Andrew Wireless Innovations Group RPT-MR701 REPEATER User Manual M0050A0B

Andrew Wireless Innovations Group REPEATER M0050A0B

Contents

Functional description and integration instructions manual

M0050A0B.doc Id.-No. 148222 Page 1 of 12 11-Mar-99
Functional description
and
integration instructions
for Repeater using
band modules with
variable bandwidth.
M0050A0B.doc Id.-No. 148222 Page 2 of 12 11-Mar-99
Contents
1Functional description........................................................................................3
2Integrating a conversion module and programming communication bus
address......................................................................................................................5
2.1 What you have to know of your system before the setting.....................................5
2.2 Setting the bus address of the module.....................................................................6
2.3 Which CF to set? .....................................................................................................7
2.4 Attenuation setting..................................................................................................8
2.5 Required software commands.................................................................................9
3Example .............................................................................................................10
4Quick reference for experienced users........................................................... 12
4.1 Frequency adjustment in UL and DL in module 1...............................................12
4.2 Frequency adjustment in UL and DL in modules 2/3/4.......................................12
4.3 Attenuation............................................................................................................12
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1 Functional description
The band module with variable bandwidth can be set to a desired centre frequency and to a
desired bandwidth.
The explanation how it works is made with reference to the following figures and exemplary
values for frequencies, bandwidths and levels.
There are two filters in one link (UL or DL) in series in the band module which can be set to a
defined centre frequency. In the example we have two filters with a bandwidth of 25 MHz
each and for demonstration purposes the frequency range is 870 to 940 MHz.
In Fig. 1 we see that filter 1 and filter 2 are both set to a centre frequency (CF) of 900 MHz.
The resulting overall response of the module is thus a 25 MHz band with a centre frequency
of 900 MHz (⇒ frequency range from 887.5 MHz to 912.5 MHz). The attenuation in the stop
band of one filter was assumed to be 40 dB. Thus, the overall attenuation of the module is
80 dB.
Fig. 1 Fig. 2
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In Fig. 2 we have the same filters but this time with different centre frequencies. The centre
frequency of filter 1 is this time 912.5 MHz and the centre frequency of filter 2 is again
900 MHz. Consequently, we get another overall response of the module as can be seen in
fig. 2. Filter 1 limits the frequency range towards lower frequencies and filter 2 towards
higher frequencies. The resulting response is thus an attenuation of 80 dB up to 881.25 MHz,
40 dB up to 893.25 MHz, 3 dB bandwidth is 12.5 MHz from 900 MHz to 912 MHz, 40 dB
attenuation from 918.75 MHz and 80 dB from 931.25 MHz. (Values exemplary!)
It is shown in the following how the centre frequency and the bandwidth of the module can be
set to desired values.
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2 Integrating a conversion module and programming
communication bus address
2.1 What you have to know of your system before the setting
Prerequisite for the adjustment is to know the bandwidth of the filters used in the module.
(Can be gained using the VER command.) With this bandwidth and the desired values the
start frequency and stop frequency (and thus the bandwidth and centre frequency) of the band
can be set. The following formula shows how to calculate the values that have to be entered.
2
1filter
Start BW
fCF +=
2
2filter
Stop BW
fCF −= ;
where
CF1 is the centre frequency of the first filter (to be entered)
CF2 is the centre frequency of the second filter (to be entered)
fStop is the stop frequency of the desired band (upper frequency)
fStart is the start frequency of the desired band (lower frequency)
BWfilter is the bandwidth of the two filters of the module (can be gained with VER command)
BW BW/2
fStart
CF1
fStop
CF2
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2.2 Setting the bus address of the module
Another thing to know is the allocation of the filters to the respective links. Each filter is
allocated to a link and a filter number by means of hex-coded rotary switches. Each rotary
switch can be set to positions from 0 to F (16 positions) by means of a small screw driver.
This adjustment is important if you want to insert a module into a Main Unit or Extension
Unit as the hex-coded rotary switches have to be set according to the Unit. If the module was
inserted in the factory you don’t have to care about that.
The following figure shows where the hex-coded rotary switches are located and the table
shows the allocation.
Filter 1 in DL Filter 2 in DL
back side
of the module
Filter 1 in UL Filter 2 in UL
Rotary switch positions:
Filter 1 Filter 2
UL DL UL DL
Main Unit 0 1 2 3
Extension Unit 1 4 5 6 7
Extension Unit 2 8 9 AB
Extension Unit 3 CDEF
Example: Rotary switch for filter 2 UL (right hand side at the bottom) in Extension Unit 2 has
to be set to A.
Note: Extension Unit 1 can also be the second module in an 8K cabinet.
Extension Unit 2 can also be the third module in an 8K cabinet.
Extension Unit 3 can also be the fourth module in an 8K cabinet.
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2.3 Which CF to set?
When setting the centre frequency the software queries for a band module (1-8). This number
has to be considered carefully because the band module with variable bandwidth contains two
filters that can be shifted independently whereas in the standard band module only one centre
frequency can be shifted. That means that one band module with variable bandwidth requires
two band module numbers to be set. The following schematic figure and the table shall
explain what band module number has to be entered.
band module with variable bandwidth
Band module number:
Main Unit Ext. Unit 1 Ext. Unit 2 Ext. Unit 3
Filter 1 1 3 5 7
Filter 2 2 4 6 8
Example: Band module number of filter 1 in Extension Unit 2 is 5 and number of filter 2 in
Extension Unit 2 is 6.
Note: Extension Unit 1 can also be the second module in an 8K cabinet.
Extension Unit 2 can also be the third module in an 8K cabinet.
Extension Unit 3 can also be the fourth module in an 8K cabinet.
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2.4 Attenuation setting
One band module with variable bandwidth needs to be addressed as if there were two modules
(see also chapter 2.2).
This means for the attenuation setting that, theoretically, there are two different attenuations
that can be set in one module. This is, however, wrong. Only one attenuation setting can be
done. This setting has always to be done in the even module number (Filter 2). Thus,
attenuation settings can only be done in module numbers 2, 4, 6 and 8.
If settings on the odd module numbers are executed the software will show dummy values but
these values are not valid. This attenuation is not really set.
Example: If you want to set the attenuation of the band module with variable bandwidth in the
Extension Unit 2 you have to set the attenuation via software in the band module 6. See also
table in chapter 2.3.
Note: Extension Unit 1 can also be the second module in an 8K cabinet.
Extension Unit 2 can also be the third module in an 8K cabinet.
Extension Unit 3 can also be the fourth module in an 8K cabinet.
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2.5 Required software commands
The software command to set the centre frequency (CF1 and CF2) of the filters and the
attenuation is given in the following.
With the SET CF command the centre frequency of a filter can be set with an accuracy of 10
kHz in GSM900 and 100kHz in GSM1800. The SET CFO (centre frequency offset) command
is for correction purposes only and should be avoided if possible. SET CFO can be set in steps
of 10 kHz from – 1000 kHz to + 1000 kHz. (See also software manual for more details.)
SET CF
Syntax: SET CF ↵
ENTER BAND MODULE (1-8): ↵
ENTER CF UL <MHz>: ↵
ENTER CF DL <MHz>: ↵
SET CFO
Syntax: SET CFO ↵
ENTER BAND MODULE (1-8): ↵
ENTER CFO UL <kHz>: ↵
ENTER CFO DL <kHz>: ↵
SET ATT
Syntax: (ENTER Repeater Number (1-4): ↵) *
ENTER BAND MODULE ( 1-8 ): ↵
ENTER MODE ( UL or DL): ↵
ENTER ATTENUATION: ↵
* (This is only valid in some earlier software versions!)
Band module number can be found in table “Band module number”.
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3 Example
An example shall demonstrate the above statements.
For further details how to perform certain actions please refer also to the Repeater manual.
Assumed we want to replace a module with variable bandwidth in an Extension Unit 2. The
desired bandwidth is 16.2 MHz and the desired centre frequency in the UL is 902.5 MHz and
in the DL 947.5 MHz. The attenuation in UL has to be set to 16 dB and 22 dB in the DL.
First thing is to check whether the rotary switches of the module are in the correct position.
The rotary switch for filter 1 in UL has to be in position 8, for filter 1 in DL in position 9, for
filter 2 in UL in position A and for filter 2 in DL in position B. (See table “Rotary switch
position”.)
The module has to be inserted and if the bandwidth of the filters in the module is not known it
can be gained with the VER command. Entering the VER command will be responded by
(amongst others) the hardware of the Repeater including the bandwidth of the filters. The
response for example of the software in a MR301A with 25 MHz filters would be:
MR301A-25, where 25 shows the bandwidth in MHz.
Next thing to do is to calculate the centre frequencies that have to be entered. With the above
given formula we get:
UL:
2
1filter
Start BW
fCF += = (902.5 – 8.1) MHz + 12.5 MHz = 906.9 MHz
2
2filter
Stop BW
fCF −= = (902.5 + 8.1) MHz – 12.5 MHz = 898.1 MHz
DL:
CF1 = (947.5 – 8.1) MHz + 12.5 MHz = 951.9 MHz
CF2 = (947.5 + 8.1) MHz – 12.5 MHz = 943.1 MHz
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Having all the values the centre frequencies can be set with the SET CF commands as
follows: (Band module number can be found in table “Band module number”.)
SET CF ↵
ENTER BAND MODULE (1-8): 5↵
ENTER CF UL <MHz>: 906.9↵
ENTER CF DL <MHz>: 951.9↵
SET CF ↵
ENTER BAND MODULE (1-8): 6↵
ENTER CF UL <MHz>: 898.1↵
ENTER CF DL <MHz>: 943.1↵
And the attenuation can be set as follows:
SET ATT
ENTER BAND MODULE ( 1-8 ): 6↵
ENTER MODE ( UL or DL): UL↵
ENTER ATTENUATION: 16↵
SET ATT
ENTER BAND MODULE ( 1-8 ): 6↵
ENTER MODE ( UL or DL): DL↵
ENTER ATTENUATION: 22↵
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4 Quick reference for experienced users
4.1 Frequency adjustment in UL and DL in module 1
Setting lower band edge:
SET CF
1
Lower band edge + (
2
bandwidthfilter )
Setting lower band edge:
SET CF
2
Upper band edge - (
2
bandwidthfilter )
4.2 Frequency adjustment in UL and DL in modules 2/3/4
Same as above with 3 and 4 / 5 and 6 / 7 and 8.
4.3 Attenuation
SET ATT
2/4/6/8 (for module 1/2/3/4)
Attenuation value

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