HP 4934A Use and care manual

SERIAL NUMBERS
This manual applies directly to instruments
with serial numbers prefixed 3648U.
For additional important information about serial numbers,
see INSTRUMENTS COVERED BY MANUAL in Chapter 3.
HEWLETT®
PACKARD
HP Part No. 04934-90054
Printed in U.K.
November 1998
Copyright © Hewlett-Packard Ltd. 1998

HP 4934A Transmission impairment Measuring Set
and Accessories Supplied

The HP 4934A is a wideband (20 Hz to 110 kHz), (20 Hz to 200 kHz option 021) Transmission
Impairment Measuring Set (TIMS). The transmission impairment measurements which can be
made are listed below.
Level Frequency
Noise
Noise with Tone
Signal to Noise
Impulse Noise
P/AR (Peak to Average Ratio)
1 J Noise to Ground
J *;j The HP 4934A can make measurements directly on leased lines or on dial-up lines. It has loop
holding capability, a monitor speaker and butt-in connection (useful for talking to the far end of the
test line).
There are four permanently stored frequencies: 404 Hz, 1004 Hz, 2804 Hz and 2713 Hz. Any other
' * four frequencies may be temporarily assigned or stored by the user.
(: J The HP 4934A can test circuits using single frequency (SF) signaling - use the SF SKIP feature,
j , SF SKIP prevents the HP 4934A from transmitting signaling frequencies in the range
i i 2600 Hz+150 Hz.

Contents
1 Getting Started
Introduction 1-1
Switch-On 1-1
Front Panel Features 1-2
Demonstrating the HP 4934A 1 -5
Demonstration 1 1-5
Demonstration 2 1-6
Error Codes 1-7
2 Making Measurements
Preliminary Setup 2-1
Connecting the HP 4934A to the Test Circuit 2-1
Dial and Hold 2-2
Dialing using the HP 4934A and a Bott-in 2-3
Receiving an Incoming Call and Holding the Line 2-4
Level and Frequency 2-5
Principles 2-5
Instrument Operation 2-7
Message Circuit Noise 2-10
Principles 2-10
How it is Measured 2-11
Instrument Operation 2-12
Noise with Tone (Notched Noise) 2-13
Principles 2-13
How it is Measured 2-13
Instrument Operation 2-14
Signal to Noise 2-15
Principles 2-15
How it is Measured 2-15
hi

Contents
Instrument Operation 2-16
Impulse Noise 2-17
Principles 2-17
Instrument Operation 2-18
P/AR (Peak to Average Ratio) 2-21
Principles 2-21
How it is Measured 2-22
Instrument Operation 2-22
Noise to Ground 2-23
Principles 2-23
How it is Measured 2-23
Instrument Operation 2-24
3 General Information
Introduction 3-1
About this Version 3-1
Specification 3-2
Safety Information 3-2
General 3-2
Safety Symbols 3-3
Statement of Compliance 3-5
Electromagnetic Compatibility (EMC) Information 3-5
Instruments Covered by Manual 3-7
Options Available 3-8
Accessories Supplied 3-9
Accessories Available 3-9
Specifications 3-10
IV

Contents
4 Installation
Introduction 4-1
Initial Inspection 4-1
Preparation for Use 4-2
Power Requirements 4-2
Line Fuse 4-2
Power Cable 4-3
Battery (Option 001 or Retrofit) 4-3
Battery 4-3
Mating Connectors (Front Panel) 4-4
Operating Environment 4-4
Cleaning 4-4
Noise Declaration 4-5
Storage and Shipment 4-5
Environment 4-5
Packaging 4-5
5 Performance Tests
Introduction 5-1
Calibration Cycle 5-1
Recommended Test Equipment 5-2
Operational Verification 5-3
Receiver Frequency 5-4
Receiver Level 5-5
Weighting Filters 5-6
Impulse Noise Count 5-9
Loss of Holding Tone 5~10
Hold Circuit 5-11
Dynamic Hold Circuit 5-13
Performance Tests 5-18

Contents
Transmitter Frequency Accuracy 5-19
Transmitter Level Range 5-20
Transmitter Level Accuracy 5 -21
Transmitter Flatness at +10 dBm 5-22
Transmitter Flatness at -40 dBm 5-24
Receiver Frequency Range/Accuracy 5-30
Receiver Level Accuracy 5-32
Message Circuit Noise Accuracy 5-34
Notch Filter Rejection 5-36
Signal to Noise Ratio Accuracy 5-37
Impulse Noise Threshold Accuracy 5-39
Noise to Ground Accuracy 5-41
Peak to Average Ratio (P/AR) Accuracy 5-43
6 Software Downloading
Introduction 6-1
Quick Download Procedure 6-2
About the DOWNLOAD Program 6-3
7 Remote Control
Introduction 7-1
The Serial Port 7~2
Serial Port Type 7-2
Baud Rates 7-2
Cable Pinout 7-3
Null Modem 7-3
Setting up for Remote Control 7-4
Connecting the TIMS to a Controller 7-4
VI

Contents
Setting the Baud Rate 7-4
Activating Remote Mode 7-4
Deactivating Remote Mode 7-4
Control Commands 1-5
Query Commands 7-8
Results Display (DISP?) Format 7-8
Range Error Messages 7-9
A Service Accessory 1 (SAl)
20 dB Amplifier/4 kHz Filter
Performance Test A-1
B Service Accessory 2 (SA2)
Power Splitter/Adder
Performance Test B-1

Contents

1
Introduction
This chapter aims to get you ready to make measurements. It takes you
through switch-on, introduces operating features and provides simple proce¬
dures to demonstrate how easy the HP 4934A is to use.
Switch-On
CAUTION Before switching on this instrument, make sure that the line voltage selector switch
is set to the voltage of the power supply and the correct fuse installed. Assure the
power supply voltage is in the specified range.
Switch on the HP 4934A by pressing the ON/STBY key.
The instrument automatically does a self-test check at power on (takes
approximately 10 seconds). During this time all front panel indicators and
displays will light (except for the CHARGING and BATTERY indicators).
When the self-test is complete the instrument starts measuring LEVEL
FREQ. Both display windows momentarily blank, then a minus sign and
period appear in the left window, followed by the transmitter level (in
dBm). The right window displays 1004 Hz.
If any of the self tests fail at power-on, an error code (see Page 1-7) is dis¬
played briefly in the right window during self-test.
Getting Started 1-1

Front Panel Features
13
IS 11
1 ON/STBY powers up the complete instrument. In the STBY (standby) mode,
only some circuits have power. When a battery is fitted the ON/STBY key has the
following indicators associated with it:
BATTERY - indicates the instrument is powered from the internal battery.
During battery operation, connect the chassis terminal on the side panel to earth
ground.
CHARGING - indicates the instrument is in the STBY (standby) mode with AC
power connected and the battery is charging.
2 HOLD (RCV) connects the receive hold circuit to the RCV port when testing
dial-up lines.
3 HOLD (TRMT) connects the transmit hold circuit to the TRMT port when testing
dial-up lines.
4 BRDG selects a high input impedance (>50 kO) for testing lines that are already
terminated. In BRDG (bridged) mode, it is still necessary to use the RCV key to
select the terminating impedance for the line you are testing. This ensures that the
HP 4934A will display the correct results.
5 DIAL connects the T (tip) and R (ring) binding posts to the TRMT port
(transmitter disconnected). To test a dial-up line or talk over the test line, connect
a butt-in to the T and R DIAL binding posts.
1>2 Getting Started

6 TRMT selects the transmitter source impedance.
7 RCV selects the receiver terminating impedance or, in bridged mode, selects the
impedance of the circuit under test.
8 REVERSE interchanges the TRMT and RCV function of the two 310 ports. The
indicators above the ports show the current function.
9 DISPLAY selects either the received or transmitted parameters for display. The
TRMT and RCV indicators above the DISPLAY key show which parameters are
being displayed.
10 ME AS selects the following measurements;
LEVEL FREQ (level frequency measurements)
NOISE (noise measurements)
NOISE W TONE (noise with tone measurements)
SIG TO NOISE (signal-to-noise measurements)
IMPULSE NOISE (impulse noise measurements)
P/AR (peak to average ratio measurements)
N.T. GND (noise to ground measurements)
11 OUTPUT LEVEL sets the transmitter output level.
12 LEVEL ZERO allows relative level measurements in the LEVEL FREQ mode.
The displayed received signal becomes the 0 dB reference when you press
LEVEL ZERO. All subsequent results are relative to this reference. The
displayed results are a measure of loss, that is a higher level than the reference is
indicated by a sign. This is standard in the telephone industry.
13 SF SKIP prevents the instrument from transmitting signaling frequencies in the
range 2600 Hz ±150 Hz. If SF SKIP is enabled the instrument automatically
prevents the selection of frequencies in this range. You can also change the SF
SJQP center frequency, see Page 2-9.
14 STEP UP, STEP DOWN, — > and change the transmit frequency value in
the LEVEL FREQ mode or the low threshold in the IMPULSE NOISE mode.
Use —> and <— to select the digit to change. The selected digit is highlighted
by a lit pointer. Change the value of the selected digit using the STEP UP and
STEP DOWN keys.
15 PERIOD selects one of the four Impulse Noise measurement periods.
16 DISPLAY displays the Impulse Noise measurement time or threshold/count
values. Only the LOW (SET) threshold value can be changed, see Page 2-20.
17 STOP allows the Impulse Noise measurement to be stopped without affecting the
Impulse Noise counter.
Getting Started 1-3

18 START RESET sets the Impulse Noise counter to zero and starts the Impulse
Noise measurement.
19 FILTER selects one of the filters in the noise measurement modes.
C-MSG
3 kHz FLAT
15 kHz FLAT
PRGM
SOkBIT
20 MONITOR VOLUME controls the volume of the monitor speaker.
21 In the LEVEL FREQ mode, the blue keys FI to F4 select preset frequencies. At
switch-on these frequencies are:
FI: 404 Hz
F2: 1004 Hz
F3; 2804 Hz
F4: 2713 Hz
New frequencies can be assigned to FI to F4, see Page 2-9.
1-4 Getting Started

Demonstrating the HP 4934A
The following demonstrations show how easy the HP 4934A is to use. A
detailed explanation of the HP 4934A measurement capability is given in
Chapter 2. The HP 4934A TRMT and RCV ports are connected by a looping
cable in these demonstrations.
Demonstration 1
A single tone measurement with the transmitter set to -10 dBm and the fre¬
quency set to 1804 Hz.
6 5
1 Use MEAS to select LEVEL FREQ.
TRANSMITTER
2 Use the TRMT key to set the transmitter impedance to 600£1
3 Display the transmitted level and frequency u.sing the DISPLAY key (TRMT
indicator lit).
4 Use the OUTPUT LEVEL control to adjust the transmitted level to -10 dBm.
5 Change the transmitted frequency to 1804 Hz using the —, STEP UP and
STEP DOWN keys.
Getting Started 1-5

RECEIVER
6 Use the RCV key to set the receiver impedance to 600fl
7 Display the received level and frequency using the DISPLAY key (RCV indicator
lit).
Demonstration 2
A noise-with-tone measurement with the holding tone set to -13 dBm and
the C-Message filter selected.
2,4
1 Use the MEAS key to select NOISE W TONE.
TRANSMITTER
2 Display the transmitted level and frequency using the DISPLAY key (TRMT
indicator lit). Level in dBm is in the left window. The frequency (fixed at 1004
Hz) is in the right window.
3 Set the level to -13 dBm using the OUTPUT LEVEL control.
RECEIVER
4 Display the received noise level using the DISPLAY key (RCV indicator lit).
5 Select the C-MSG filter using the FILTER key.
6 Read the weighted noise in dBmC in the left window. The received frequency is
in the right window.
1-6 Getting Started

Error Codes
The error codes are described in the following table:
Code
Description
Err 1 to Err 6
Instrument faulty, see Service Manual.
Err 7
Received holding tone level too high or too low- check
transmitted level or circuit under test.
Err 8
Impulse Noise threshold set too high - adjust.
sign in right
Loss of holding tone during pulse Noise measurement - only
window
a warning, the instrument continues counting.
Getting Started 1-7

2
Making Measurements
Preliminary Setup
Connecting the HP 4934A to the Test Circuit
CAUTION Ensure no more than 200 V dc or 10 V rms at 60 Hz is connected between tip and
ring of the TRMT or RCV jacks.
1 The two 310-type jacks of the HP 4934A can function as a Transmitter output or
Receiver input. Pressing the REVERSE key causes the function of the two 310-
type jacks to be reversed. The current function of the ports is indicated by the
indicators below the REVERSE key.
2 If the line to be tested is already terminated, press BRDG.
3 Select the receiver input impedance using the RCV key - 135,150,600, 900 or
12000. When operating in BRDG (bridged) mode, still ensure the correct
impedance is selected.
Making Measurements 2-1

4 Select the transmitter output impedance using the TRIWT key -135,150,600,900
or 1200Q.
Dial and Hold
The HP 4934A can be used with a butt-in to dial up lines or for talking along
a line. The HP 4934A can hold lines which require a DC current to maintain
the connection once the butt-in is disconnected.
The diagram below shows how the hold, dial and reverse functions work.
2-2 Making Measurements