Agilent Technologies 8924C Service manual

Contents
Section 1—Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Test Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Base Station (Test Set) Power Transitions . . . . . . . . . . . . . . . . 2
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Section 2—Test Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Section 3—Connecting the Equipment . . . . . . . . . . . . . . . . . . . . . 4
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Section 4—Test Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Section 5—Configuring the Test Set . . . . . . . . . . . . . . . . . . . . . . . 8
Setting the RF Level Offset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Setting the Pilot and Traffic Channels . . . . . . . . . . . . . . . . . . . . 8
Setting the Channel and Protocol . . . . . . . . . . . . . . . . . . . . . . . 10
Setting the CDMA Transmitter Power
Test Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Section 6—Setting Up a 20 dB Increment on the Test Set . . . . 12
Section 7—Determining the Test Set’s Trigger Time Delay . . . 12
Section 8—Configuring the Spectrum Analyzer
and Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Setting “CDMA Config” Options . . . . . . . . . . . . . . . . . . . . . . . 14
Setting the RF Channel Function . . . . . . . . . . . . . . . . . . . . . . . 15
Setting the Time Response Function . . . . . . . . . . . . . . . . . . . . 15
Appendix 1—Background on Open and Closed Loop
Power Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Open Loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Closed Loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Appendix 2—The Effect of Closed Loop Control
on the Open Loop Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Appendix 3—Determining Cable Connection Losses . . . . . . . . 18
External Power Meter Method . . . . . . . . . . . . . . . . . . . . . . . . . 18
Using the Agilent 8924C Test Set . . . . . . . . . . . . . . . . . . . . . . . 18
Appendix 4—Trigger Signal Description . . . . . . . . . . . . . . . . . . . 19
Making a Trigger Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Trigger Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Open Loop Power-Control Time-Response Test
This product note will help you measure the “time
response of open loop power control” for a CDMA
mobile cellular telephone. The equipment and pro-
cedures in this document apply to CDMA mobile
cellular telephones based on TIA/EIA/IS-95-A, or
related industry standards.
Section 1—Introduction
The open loop power control time-response is
defined as the amount of time (t) it takes the
mobile phone to respond to and acquire equilib-
rium following a step increase in base station
power, ∆Pin.
This test verifies that the mobile is capable of
adjusting its transmit power throughout its dynamic
range of transmission within a power versus time
mask determined by applicable standards.
An example of this mask, with a ∆Pin = 20 dB and
∆t = 100 ms, is shown in Figure 1. For TIA/EIA/IS-
95-A, the upper and lower limits of this mask are
determined by the equations shown on the follow-
ing page.
Agilent 8924C
CDMA Mobile Station Test Set
Product Note

2
Upper Limit Equations
For: 0 <t <24 ms: Max [1.2 x | ∆Pin | x (t/24), | ∆Pin |
x (t/24)+2.0 dB] +1.5 dB
For: t ≥24 ms: Max [1.2 x | ∆Pin |, | ∆Pin | +0.5 dB] +1.5 dB
Lower Limit Equation
For: t ≥0 ms: Max [0.8 x | ∆Pin | x [1–e(1.25–t)/36] –2.0 dB,0] –1 dB
Where:
•t is expressed in milliseconds,
•∆Pin is expressed in units of dB
• Max [x, y] is the maximum of the x and y com-
ponents in the upper and lower limit equations.
Test Parameters
The following are general test parameters for the
open loop power control time-response test (from
industry standard IS-98-A, other standards should
be similar).
• Test set power range into phone’s receiver:
–25 dBm to –104 dBm
• Pilot channel level: –7 dB
• Traffic channel level: –7.4 dB
Base Station (Test Set) Power Transitions
1. The open loop power control time-response test
is initiated at a power level of –60 dBm (base
station). See Figure 2.
2. The test set power is increased by a step of
20 dB to a power level of –40 dBm.
3. The test set power is decreased by a step of
20 dB to a power level of –60 dBm.
4. The test set power is decreased by a step of
20 dB to a power level of –80 dBm.
5. The test set power is increased by a step of
20 dB to a power level of –60 dBm.
References
• Telecommunications Industry Association,
Industry Standards TIA/EIA/IS-98-A (Section
10.4.2—Time Response of Open Loop Power
Control), Sept. 10, 1997
• American National Standards Institute (ANSI).
ANSI J-STD-018 Recommended Minimum
Performance Requirements for 1.8 to 2.0 GHz
Code Division Multiple Access (CDMA)
Personal Stations (Section 4.4.2—Time
Response of Open Loop Power Control)
• ARIB STD-T53 Ver. 1.0, CDMA Cellular System,
Association of Radio Industries and Business,
1-4-1 Kasumigaseki, Chiyoda-ku, Tokyo 100,
Japan, October 1997
Figure 2. Base Station Power Transitions
Figure 1. Example Limits for the Open Loop Response

3
Section 2—Test Equipment
Equipment Notes
8924C CDMA Mobile Station Test Set The Test Set must be equipped with electronic attenuators. NOTE: To determine if the
Agilent 8924C Test Set is equipped with an electronic attenuator, access the Test Set’s
TESTS screen (this procedure will erase any other IBASIC program stored in the test set):
1. Press the TEST key.
2. Select Procedure Location: ROM.
3. Select Procedure Filename: ICONFIG3.
4. Press k1 (Run Test) and look for A5 Input with Electronic Attenuator.
83236B PCS Interface This PCS interface is needed if performing PCS band tests
MINIMUM REQUIRED OPTIONS for 85725C open loop measurements:
• Option 004—Precision Frequency Reference (or equivalent external 10 MHz precision
frequency reference)
• Option 101—Fast Time Domain Sweeps (if Option 151 is installed DO NOT INSTALL
Option 101)
PREFERRED and RECOMMENDED OPTIONS for 85725C:
• Option 140—Narrow Resolution Bandwidth and Precision Frequency Reference (narrow
bandwidth for ACPR measurements; includes precision reference same as Option 004)
• Option 053—Improved CDMA Amplitude Accuracy (for cellular and PCS bands)
•Option 151—DSP, Fast ADC, and Digital Demodulator (provides faster CDMA measurements)
•Option 160—CDMA firmware (for use with option 151)
OTHER SUGGESTED OPTIONS:
• Option 041—GPIB and Parallel Interface
• Option 105—Time-Gated Spectrum Analysis
To determine which spectrum analyzer option is installed in the spectrum analyzers:
1. Press CONFIG key.
2. Press More 1 of 3 softkey.
3. Press SHOW OPTIONS softkey.
85725C CDMA Measurements Personality This assembly is installed in the 859XE spectrum analyzer.
CDMA Mobile Phone An appropriate antenna connector or cable is required for the phone.
Shielded RF Isolation Box This item is optional but recommended.
Power Splitter A resistive or transformer-coupled power splitter is acceptable. It must be able to handle
the output power of the phone (approximately 25 dBm max). Example: Mini-Circuits resis-
tive power splitter/combiner, p/n ZFRSC-2050 (dc to 2 GHz).
Trigger Cable Use a 15-pin male D-connector to BNC male connector cable. This cable is used to send
trigger signals to the 859XE Spectrum Analyzer from the 8924C Test Set. NOTE: See
Appendix 5 in this document for instructions on how to build this cable.
RF Cable Three low-loss shielded RF cables with type-N (male) connectors to mate with the power
splitter, RF shielded box, and CDMA telephone.
One of the following Agilent Technologies
spectrum analyzers is needed:
• 8593E Spectrum Analyzer
• 8594E Spectrum Analyzer
• 8595E Spectrum Analyzer
• 8596E Spectrum Analyzer

4
Figure 3. Setup for Cellular Band Phones
Section 3—Connecting the Equipment
For CDMA cellular band mobile phones see Figure
3; for CDMA PCS band mobile phones see Figure 4.
1. Connect the CDMA phone to the power splitter.
Ensure that the CDMA phone is properly
shielded against external RF interference. An
example of interference is an active base sta-
tion transmitting on the same channel as the
mobile unit under test.
2. Connect one output end of the power splitter to
the 50 W input of the spectrum analyzer.
3. Connect the other output end of the power
splitter to the RF IN/OUT port on the test set
for cellular frequencies; or, to the RF IN/OUT
port on the PCS interface for PCS frequencies.
4 Connect the trigger cable from the AUX CON-
TROL port (15-pin D-connector) on the back of
the test set to the EXT TRIG INPUT (TTL) BNC-
connector on the back of the spectrum analyzer.
A trigger signal is required to activate the open
loop test once it has undergone a step change
in power. For instructions on making a trigger
cable, see Appendix 5—Trigger Cable and
Trigger Signal Description.
References
•Agilent Technologies E8285A CDMA Mobile
Station Test Set Reference Guide, Chapter 2,
Description of Connectors (SA TRIG OUTPUT),
pub. number E8285-90018
•Agilent Technologies 859XE Users Guide, pub.
number 08590-90301
•Agilent Technologies 85725X CDMA
Measurements Personality User’s Guide, pub.
number 85725-90010

5
Figure 4. Setup for PCS Band Phones

6
Figure 6. Time Response and Open Setup Functions
Figure 5. CDMA TRANSMITTER POWER RANGE TEST Screen
Section 4—Test Procedure
This section is a step-by-step measurement proce-
dure. Some of the following steps will refer you to
other sections in this document. After you com-
plete the instructions in those sections, return to
this section to continue the procedure.
1. Connect equipment as described in Section 3—
Connecting the Equipment. Power-up the
instruments but not the mobile phone.
2. Configure the test set as described in Section
5—Configuring the Test Set.
3. Set the RF power increment to 20 dB on the
test set as described in Section 6—Setting Up a
20 dB Increment on the Test Set.
4. Calibrate channel power on the test set by
accessing the CDMA TRANSMITTER POWER
RANGE TEST screen (see Figure 5 item 6). For
details refer to section 5, the subsection titled
“Setting the CDMA Transmitter Mode.”
5. Measure the delay between the test set’s trigger
signal and power transmission step using the
spectrum analyzer as described in Section 7—
Determining the Test Set’s Trigger Time Delay.
Record the trigger delay of the test set. Then
convert the value from milliseconds to
microseconds (milliseconds x 1000 = microsec-
onds). It will be entered into the spectrum ana-
lyzer’s DELAY field.

6. Configure the spectrum analyzer and software
as described in Section 8—Configuring the
Spectrum Analyzer and Software. Enter the
recorded delay time into the DELAY field of the
Time Response/Open Setup function, see Figure 6.
7. Turn on the CDMA phone. On the test set’s
CDMA TRANSMITTER POWER RANGE TEST
screen, set the following:
7a. Set Closed Loop Pwr Cntl field to Closed Loop
(see Figure 5, item 1).
7b. Set Sctr A Pwr field set –40 dBm (see Figure
5, item 7).
7c. Set Output Atten Hold field (see Figure 5,
item 8) to Off.
7d. Set Traffic Data Mode to Svc Opt 1 (see Figure
4, item 3, this will be changed to Svc Opt 2
in step 9), or to normal voice-call service
option for the phone type.
8. Select the test set’s CDMA CALL CONTROL
screen. After the phone indicates service, dial a
number and place a call from the phone to the
test set. Wait until the call is connected.
9. Press the test set’s END CALL key.
9a. Set the Traffic Data Mode to Svc Opt 2
9b. Press the test set’s CALL key to connect a
call in data loopback mode at full rate.
(The phone will usually display a message
indicating LOOP MODE.)
10. Once a call is connected, go to the CDMA
TRANSMITTER POWER RANGE TEST screen
on the test set and:
10a. Change the Closed Loop Pwr Cntl field from
Close Loop to Open Loop (see Figure 5, item 1).
10b. Change the Output Atten Hold field to on (see
Figure 5, item 8).
10c. Change the Sctr A Pwr field to –60 dBm (see
Figure 5, item 7). Remember to use up and
down arrows.
11. On the spectrum analyzer, on the Time
Response screen (see Figure 6), select the OPEN
LOOP softkey. This will start the open loop time-
response test. The message Waiting for Ext Trig
appears on the screen (see Figure 7) after a
short delay
12. Press the SET REF LVL softkey (see Figure 7, item
2). Enter 15 dBm. Press the ENTER key. This
adjusts the spectrum analyzer’s input attenua-
tor and reference level to allow viewing of the
full range of power transitions.
13. Step increase Sctr A Pwr field to –40 dBm. The
time response will be displayed on the spec-
trum analyzer.
Figure 7. Spectrum Analyzer Waiting for External Trigger
7

8
14. A 20 dB step change of the test set’s power will
trigger the time response test. Figure 8 shows
the results of a 20 dB decrease in the test set’s
transmitted power. Note that PASS or FAIL is
displayed in the lower right corner.
15 Step decrease Sctr A Pwr field to –60 dBm. The
new time response will be displayed on the
spectrum analyzer.
16. Step decrease Sctr A Pwr field to –80 dBm. The
new time response will be displayed on the
spectrum analyzer.
17. Step increase Sctr A Pwr field to –60 dBm. The
new time response will be displayed on the
spectrum analyzer.
NOTE: The REPEAT MEAS softkey on the spectrum
analyzer can be used to reinstate the open loop
test (see Figure 8). However the open loop test will
automatically reset for another measurement, so
this softkey does not have to be pressed.
Figure 8. Spectrum Analyzer—Open Loop Response Test
Results

9
Figure 9. CONFIGURE Screen
Figure 10. CDMA GENERATOR CONTROL Screen
Section 5—Configuring the Test Set
As an example, the following test set screens show
the appropriate settings for testing a U.S. PCS
phone. The screens presented are accurate with
respect to firmware revision A.05.30. Future revi-
sions will be similar but are not guaranteed to be
the same.
Setting the RF Level Offset
Access the CONFIGURE screen, see Figure 9.
1. The RF Level Offset field must be On in order to
activate the RF In/Out field (item 2).
2. The RF In/Out field should be set to the attenua-
tion value determined by the methods described
in Appendix 3—Determining Cable Connection
Losses. This will compensate for losses encoun-
tered by the power splitter and cables. This
value is entered as a negative offset (loss).
Setting the Pilot and Traffic Channels
Access the CDMA GENERATOR CONTROL screen,
see Figure 10.
1. For sector A (the left column on the screen),
the Pilot channel field (Walsh channel 0) must
be set to –7.0 dB (for testing EIA/TIA/IS-98-A).
2. The Traffic channel (Walsh channel 8 through 31
or 33 through 63) must be set to –7.4 dB (for
testing to EIA/TIA/IS-98-A).

10
Setting the Channel and Protocol
Access the CDMA CALL CONTROL screen, see
Figure 11.
1. Set the RF Chan Std field (item 3) to the appro-
priate standard.
1a. For example, for U.S. PCS frequencies, set
this field to US PCS.
1b. For U.S. cellular frequencies, set this field
to MS AMPS.
1c. For CDMA phones for use in Japan, choose
Japan CDMA. The RF Channel field is auto-
matically updated with the starting chan-
nel within the given standard.
2. Enter the appropriate channel value in the RF
Channel field (item 1). The manufacturer or
service provider programs the phone to the
appropriate RF channels. If the RF channel is
not known or incorrectly entered into the test
set, the phone will start to scan all the possible
channels in the phone’s channel list. If an out-
side base station of higher power is received,
the phone will lock onto it and discontinue its
search. For some phones, this is a long process,
therefore, it is recommended that the appropri-
ate channel value is known and entered into
the RF Channel field.
3. Enter the appropriate protocol for the selected
channel standard into the Protocol field (item 2).
For example:
3a. For U.S. CDMA PCS frequencies, select
JSTD-008.
3b. For U.S. CDMA cellular frequencies, select
IS-95A or TSB-74.
3c. For Japanese CDMA, select ARIB T53.
Figure 11. CDMA CALL CONTROL Screen

Setting the CDMA Transmitter Power Test Mode
Access the CDMA TRANSMITTER POWER RANGE
TEST screen, see Figure 12.
1. Set the Closed Loop Pwr Cntl field (item 1) to
Closed Loop to begin the test. This field controls
the sequence of the “punctured” power control
bits. In open loop mode the test set sends alter-
nating 0 and 1 bits.
NOTE: In closed loop mode the test set sends the
appropriate power control bits to control the
transmitted power level of the phone. Closed
loop mode should be active while a call is being
connected. Open loop mode is activated after a
call has been connected and throughout the
remainder of the open loop power control time-
response test. For more information, see
Appendix 1—Background on Open and Closed
Loop Power Control.
2. Set the Drop Timer field (item 2) to Off. This
stops the test set from disconnecting the call
even when it cannot detect the phone’s trans-
mitted signal. This may occur when the test set
is transmitting at the –40 dBm level.
3. Set the Traffic Data Mode field (item 3) to Svc Opt 2
(9600 bps) or Svc Opt 9 (18800 bps), depending
on the standard.
4. Set the Data Rate field (item 4) to Full.
5. The power meter is able to operate as either a
channel-power meter or an average-power
meter. Select Chan Power (item 5). For this test
the channel power meter is used because it
gives a channel power reading specific to the
reverse channel bandwidth that is occupied by
the phone.
6. The Power Meas field (item 6) is used to cali-
brate the channel power meter. Set this field to
Calibrate, but, before the calibration can pro-
ceed, the RF IN/OUT and RF OUT Only ports
on the PCS interface, or the RF IN/OUT and
DUPLEX OUT ports on the test set, must be
connected together with a short RF cable. Refer
to the Agilent 8924C Applications Guide, chap-
ter 1, pub. number 08924-90021, for assistance
in calibration.
7. The sector-A power, Sctr A Pwr, field (item 7) is
used to change the transmitted power level of
the test set in steps of ±20 dB. The power level
steps must be entered in whole values and not
incremented by turning the knob. Use the up-
and down-arrow keys to increment values in
20 dB steps. See Section 6—Setting Up a 20 dB
Increment on the Test Set.
8. The Output Attn Hold field (item 8) is set to On
only for PCS phones. This field is used to hold
the setting of the mechanical relay attenuator
in the PCS interface. (For more information see
Appendix 4—Holding the PCS Interface’s RF
Attenuator.)
9. The Chan Power reading can be compared to the
Ideal Mobile Power reading (item 9) to obtain a
measure of how effectively the phone operates
under the open loop power control.
11
Figure 12. CDMA TRANSMITTER POWER RANGE TEST
Screen

12
Section 6—Setting Up a 20 dB Increment on the
Test Set
You can increase or decrease the Sctr A Pwr by 20 dB
with a press of one button. Listed below are the
steps to set up a 20 dB increment adjustment:
1. Go to the CDMA TRANSMITTER POWER
RANGE TEST screen, see Figure 13.
2. Move the cursor to the Sctr A Pwr field (item 7).
3. Press the Incr Set key on the front panel of the
test set.
4. Typically I = 1.00 will appear in the Sctr A Pwr
field. Using the DATA KEYS, enter the value 20
and then press the knob.
5. By using the up- and down-arrow keys (or turn-
ing the knob) on the front panel of the test set,
the power will increase or decrease in incre-
ments of 20 dB each time an arrow key is
pressed (or the knob is turned).
Section 7—Determining the Test Set’s Trigger
Time Delay
In order to perform an accurate open loop power
control time-response test, it is important to accu-
rately determine the delay between the trigger sig-
nal and the actual power step at the test set’s out-
put. Inaccurate delay times will cause the test to
start before the power level from the test set has a
chance to change. This will often cause the test
results to indicate a failure. For details, see
Appendix 5—Trigger Cable and Trigger Signal
Description.
1. Turn off the phone.
2. On the spectrum analyzer:
2a. Press the PRESET key on the front panel.
2b. Press the Spectrum Analyzer softkey.
3. On the test set, set the Sctr A Pwr field in the
CDMA TRANSMITTER POWER RANGE TEST
screen to –40 dBm (see Figure 13, item 7).
4. For testing PCS phones only, on the test set, set
the Output Atten Hold field to on (see Figure 13,
item 8).
5. On the spectrum analyzer:
5a. Press the FREQUENCY key.
5b. Enter the center frequency that the test set
(forward channel) is operating on. For
example: RF Chan Std = US PCS; RF
Channel = 500; forward channel frequency
= 1955 MHz.
5c. Press the ENTER key (same as Hz/µv/µs
key).
5d. On the spectrum analyzer, press the SPAN
key.
Figure 13. CDMA TRANSMITTER POWER RANGE TEST
Screen

13
5e. Enter 0 Hz, and press the ENTER key.
5f. Press the BW Band Width key.
5g. Enter 3 MHz, press the ENTER key.
5h. Press the AMPLITUDE key.
5i. Press the REF LEVEL softkey and enter –25 dBm.
Press the ENTER key.
5j. Press the ATTEN softkey and ensure it is set
to manual, MAN. Enter an attenuation of 0 dB
and press the ENTER key.
6. Change the test set’s Sctr A Pwr field from –40 to
–60 dBm to ensure that the setup is correct. The
spectrum analyzer display should show a 20 dB
drop.
7. On the spectrum analyzer press the SWEEP
key.
7a. Enter 20 ms.
7b. Press the ENTER key
8. Set the test set’s Sctr A Pwr field from –60 to
–40 dBm.
9. On the spectrum analyzer press the TRIG key.
9a. Press the SWEEP softkey (next to the dis-
play) and set it to single, SGL.
9b. Press the EXTERNAL softkey.
NOTE: The spectrum analyzer is now ready
to measure the time delay between the
E8285A trigger signal going high and the
E8285A RF output level changing 20 dB.
10. Change the test set’s Sctr A Pwr field from –40 to
–60 dBm. It typically falls within 15 to 20 ms.
Each major graticule line from left to right is
2 milliseconds (typically set trigger delay is
between 15 and 20 ms).
11. On the spectrum analyzer measure the time
delay that appears on the display.
12. Record this delay time, it will be used later in
the test procedure.
13. To reset the spectrum analyzer for another trig-
ger delay measurement:
12a. Press the FREE RUN softkey.
12b. Press the EXTERNAL softkey.
14. Change the test set’s Sctr A Pwr field by a step
of 20 dB. Try it from –40 dBm to –80 dBm. The
time delays should be almost identical.
15. When the trigger delay measurements are com-
plete:
15a. Press the AMPLITUDE key.
15b. Press the ATTEN softkey.
15c. Choose AUTO.

14
Section 8—Configuring the Spectrum Analyzer
and Software
First install the Agilent 89725C software follow-
ing the instructions in the 85725C user’s guide,
Chapter 1—Getting Started, step 1 “Load the
CDMA Measurement Personality.” For best accu-
racy, you should also perform step 2, the spectrum
analyzer’s calibration routines. When the 85725C
CDMA Measurements Personality software is
installed in the spectrum analyzer, the CDMA
ANALYZER menu options (see Figure 14) are
available.
Setting “CDMA Config” Options
1. Press the MODE key.
1a. Press the CDMA ANALYZER softkey.
1b. Press the CDMA Config softkey of the CDMA
ANALYZER main menu 1 of 3 (see Figure
11). The CDMA Config options sub-menu 1
of 3 appears.
2. Press the BASE MOBILE softkey until MOBILE is
underlined. This tunes the spectrum analyzer
to the reverse link of the selected channel.
3. Press the MS EXT ATTEN softkey (on sub-menu 1
of 3) enter the value for the attenuation meas-
ured from the power splitter and the cables
connecting the test set to the spectrum analyzer.
This is a positive number since the field is
assuming it is an attenuation loss.
For example:
3a. 6 dB of attenuation is measured (see
Appendix 3—Determining Cable
Connection Losses).
3b. Enter 6 dB in the MS EXT ATTEN return
field.
3c. Press the ENTER key on the spectrum ana-
lyzer.
4. Press More 1 of 3 field to obtain CDMA Config
sub-menu 2 of 3 (see Figure 12).
5. The TRIG field must be set to EXT (external).
This enables the trigger from the test set.
6. Press More 2 of 3 softkey to obtain CDMA Config
sub-menu 3 of 3 (see Figure 12).
7. Press the Std/Band softkey. Then press the soft-
key that matches the standard you are using.
For example, JSTD-008 for U.S. PCS frequencies.
8. Press the More 3 of 3 softkey to return to CDMA
Config sub-menu 1 of 3 and press the Main
Menu softkey.
Figure 14. CDMA ANALYZER Main Menu and CDMA Config Menu Options

15
Figure 16. Time Response Function
Setting the RF Channel Function
1. Select the RF Channel softkey on the CDMA
ANALYZER main menu 1 of 3, the RF Channel
options will appear (see Figure 15).
2. Press the CHANNEL NUMBER softkey and enter
in the correct channel operation number for
the phone in this field, then press the ENTER
key. The CENTER FREQ field will automatically
update with the center frequency of the
entered channel.
3. Press the Main Menu softkey to return to the
CDMA ANALYZER main menu screen.
Setting the Time Response Function
1. Press the More 1 of 3 softkey on the CDMA ANA-
LYZER main menu to go to menu 2 of 3 (see
Figure 16).
2. Press the Time Response softkey to access the
time response test functions (see Figure 16).
3. Press the Open Setup softkey of the Time
Response functions to conFigure the open loop
test setup functions (see Figure 16):
3a. Press the SWP TIME softkey. Set the sweep
time to 100 ms and then press the ENTER
key. (100 ms is the measurement time spec-
ified by IS-98-A.)
3b. The DELTA PWR field determines the step
value at which the mask limits change with
respect to each trigger signal. 20 dB is the
default value of this field (20 dB is the step
specified by IS-98-A).
Figure 15. RF Channel Options

16
3c. Press the DELAY softkey. Enter the trigger
delay time measured in Section 8—
Determining Trigger Time Delay. The
delay time is entered in microseconds, for
example: 17 ms delay time = 17,000 µs.
Press the ENTER key twice. It is important
to enter an accurate delay time in order to
obtain accurate test results. The test may
fail frequently if the trigger does not occur
at the time of power transitions.
3d. Press the Previous Menu softkey to return to
the Time Response menu screen.
References
•Agilent Technologies 89725C Measurements
Personality User’s Guide, pub. number 85725-
90010
• For Agilent Technologies 859XE setup and con-
figuration refer to the User’s Guide, pub. num-
ber 08590-90301.

17
Appendix 1—Background on Open and Closed
Loop Power Control
The effectiveness of CDMA as a method to increase
call capacity is partially determined by how effec-
tive the transmitted power of each mobile can be
accurately controlled and minimized. The goal of
the mobile is to transmit its signal with the least
amount of power capable of producing a detectable
signal at the base station; any more power will sim-
ply be added noise to the system. In order to accu-
rately control the mobile’s power (reverse link),
two methods are used: open loop power control
and closed loop power control.
Open Loop
The open loop power control process is performed
when the phone is in an idle state (not on a call).
Open loop power control assumes that the path
loss is the same on the reverse path as it is on the
forward path. The mobile can determine the cor-
rect transmit power (reverse link) by monitoring
the base station’s transmit power (forward link)
and subtracting a constant. The open loop power
control response for cellular and PCS frequencies
are described by the following equations:
Cellular Equation
Receive Power (Forward Link) + Transmit Power
(Reverse Link) + Nominal Power + Initial Power
= –73 dBm
PCS Equation
Receive Power (Forward Link) + Transmit Power
(Reverse Link) + Nominal Power + Initial Power
= –76 dBm
Closed Loop
Closed loop power control accompanies the open
loop power control process. The base station moni-
tors the received signal from the mobile and deter-
mines if the signal is “just good enough to maintain
a link.” Every 1.25 milliseconds or 800 times a sec-
ond the base station commands the mobile to raise
or lower its transmit power by a step of 1 dB based
on the signal it received from the mobile. Therefore,
the power transmitted from the mobile is never
constant for more than 1.25 ms.
The base station sends the closed loop power con-
trol instruction to the mobile by replacing a bit of
voice data with a power control bit. For instance, if
a one bit is received the mobile knows to reduce its
power by 1 dB, and if a zero bit is received the
mobile knows to increase its power by 1 dB. This
process is called “puncturing.”

18
Appendix 2—The Effect of Closed Loop Control
on the Open Loop Test
Since this test is only concerned with the open
loop response it would be ideal to eliminate the
effects of the closed loop power control on the
reverse power transmission. This is not entirely
possible. Due to the various design limitations that
phone manufacturers have in their products, the
test set is unable to tell the phone to turn off the
closed loop control.
The open loop test that is described in this paper
is not exclusively open loop controlled, the closed
loop control is still present because the phone is
on a call. The test set has the capability of going
into a “virtual open loop mode” by alternating the
power control bits (between digital 0 and 1). This
gives the appearance of being exclusively in open
loop power control mode, but with an error of ±1 dB
at best.
This can cause a problem when the base station is
transmitting near the noise floor. Since there is no
form of error correction associated with the “punc-
tured” power control bits, they are easily received
in error. Once the forward link approaches the
noise floor, the Frame Error Rate (FER) increases,
which will increase the probability of receiving
consecutive similar power-control bits. At such low
signal levels this error could be enough to cause a
dropped call or failure of the open loop time-
response test.
Simply by monitoring the FER you can tell when
the noise floor is compromising your measure-
ments. The noise floor is not standard, it can vary
from time to time and location to location. Just
because your phone passes the tests in one loca-
tion doesn’t mean that the phone will pass in a dif-
ferent location or at a different time. Therefore, it
is very important to have your phone properly
shielded from outside noise and interference dur-
ing testing.

19
Appendix 3—Determining Cable Connection
Losses
In order to obtain accurate power measurements a
few steps need to be taken. First, always calibrate
the channel power on the test set when you have
powered down the test set or if significant changes
have been made to the configuration of the test set
(channel changes, cellular to PCS operation, and so
forth).
Second, you must account for losses that have
occurred through the transmission medium
between the connected devices. Since you are
using a power splitter and two cables, these losses
need to be taken out of the power transmission
process. The test set allows you to enter an RF
level offset. The test set transmits its signal at a
level above or below the entered sector power,
depending on the sign (+ or –) of the attenuation
entered into the RF Level Offset field. (Refer to
Section 6—Setting Up a 20 dB Increment on the
Test Set; and Section 7—Determining Test Set
Trigger Time Delay.)
External Power Meter Method
In order to determine the attenuation of the power
splitter and the two cables, an external power
meter can be used. Listed below are the steps you
need to take to find your RF power compensation:
1. Zero the power meter.
2. Connect the power meter directly to the test
set’s DUPLEX OUT port; or, the PCS interface’s
RF OUT Only port.
3. On the CONFIGURE screen:
3a. Set RF Level Offset field to Off.
3b. Set the Output Port field to Duplex for cellu-
lar band, or only for PCS.
4. Go to the CDMA CALL CONTROL screen:
4a. If no PCS interface is used, set Sctr A Pwr
field to dBm.
4b. If a PCS interface is used, set to –11 dBm.
5. With the power meter, measure the power out
of the test set.
6. Connect the cables and splitter to the DUPLEX
port, or RF OUT Only for the PCS interface.
Include every connection from the test set up
to but not including the cellular phone. This
includes a car kit or break out box if used.
7. With the power meter, measure the power at
the end of the cables and splitter.
8. Subtract the second measurement from the
first to obtain your RF level offset.
Using the Agilent 8924C Test Set
To determine the attenuation of the power splitter
and the cables, the test set can be used. Refer to
“Determining RF Path Loss” in Chapter 1 of the
Agilent Technologies 8924C Application Guide,
pub. number 08924-90021.

20
Appendix 4—Holding the PCS Interface’s RF
Attenuator
This appendix applies only if an Agilent 83236B
PCS Interface is used.
A mechanical attenuator is used in the PCS inter-
face. Mechanical attenuators when switched in and
out of operation can produce transient responses
as they are relays that open and close. While a
relay is in an open state, the open loop power con-
trol of the mobile notices a loss of power from the
base station and starts transmitting the reverse
signal at a higher power level.
When the mechanical attenuator completes its
transition (typically 10 ms to 50 ms) the forward
power returns to a higher value and the mobile’s
open loop power control notices that it is transmit-
ting the reverse signal at too high a power and
starts to lower its signal strength. This variation is
undesirable for the open loop timing measurement.
To correct this problem, the mechanical attenuator
in the PCS interface is set in a fixed state, and the
RF output level is varied using the transit-free elec-
tronic attenuator in the test set. (The fixed state is
selected when the Output Atten Hold field in the
CDMA TRANSMITTER POWER RANGE TEST
screen is set to on.)
The maximum power that the test set and the
PCS interface will be transmitting in this test will
be –40 dBm so that is the attenuator hold level.
Once held, RF output levels down to approximately
50 dB lower than the “hold” level are accurate.
However, output levels higher than the “hold” level
are inaccurate.