TF960
6GHz Universal Counter
INSTRUCTION MANUAL
Table of Contents
Introduction 2
Specification 3
EMC 7
Safety 8
Connections 8
Manual Operation 10
Remote Operation 17
Maintenance 23
This manual is 48581-1440 Issue 2
Note: The latest revisions of this m anual and device driver can be downloaded from:
http:tti1.co.uk/downloads/manuals-rf.htm
1
Introduction
The TF960 is a portable, battery-operated, universal counter with a large 0.5" 10-digit liquid
crystal display (LCD). The frequency range is from below 0.001Hz to over 6GHz and
measurement functions include f requency, period, ratio, pulse width and count.
The instrument uses a high quality tem per ature compensated internal frequency reference which
has a low aging rate and is stable to within ±1ppm over the full temperature range. Its short
warm-up time allows accurate measurements to be made even under portable battery powered
conditions.
Input A has configur able coupling ( AC or DC), input impedanc e ( 1MΩ or 50Ω), attenuation
(1:1 or 5:1), threshold (fully variable) and active edge and can be used for frequencies in the
range 0.001Hz to over 125MHz. Input B is a nominal 50Ω input for frequencies in the range
80MHz to 3GHz. Input C is a nominal 50Ω input with an N-type connector for frequencies in the
range 1GHz to over 6GHz. An External Reference input is provided and changeover from the
internal timebase is automatic when an external reference standard is connec t ed.
For frequency, period and frequency ratio functions the instrument uses a reciprocal counting
technique to provide high resolution at all frequencies. 8 significant digits of answer are
produced in a 1 second measurement time, 9 dig its in 10s and 10 digits in 100s with a granular it y
of less than 2 counts in the least significant digit.
Indicators show measurement input configuration & function, measurem ent time & status,
external reference connection, low battery and the units of the measurement which may be Hz,
kHz, MHz, ns, us, ms or s.
The instrument has a USB interf ace which allows it to be remotely contr olled using s er ial
communication via a computer’s USB port. The remote com m ands of predecessor instruments,
the TF830 and the TF930, are compatible with the TF960 command set
The instrument operates from internal rechargeable NiMH batteries which give typically 24 hours
operating life. The universal AC charger supplied will recharge the batteries in less than 4 hours
and can be used for continuous AC operation. The instrument will also automatically be powered
from a standard USB port when connected (whether remot e cont rol is in use or not) but this will
not charge the batteries.
This instrument is fully compliant with EN61010-1 Safet y and EN61326 EMC standards.
2
or 50Ω nominal (AC coupled only).
< 500kHz to > 125MHz (50Ω, AC coupled).
AC coupled:
Average ± 50mV (1:1 attenuation) or ± 250mV (5:1 attenuation).
50Ω nominal (AC coupled) in-band. 250kΩ at DC.
>100k
AC coupled.
Input Specificat ions
Input A
Specification
Configurable options
Input coupling:
Input impedance:
Attenuation:
Active edge:
Low pass filter:
Trigger threshold:
Input Impedance:
Frequency Range:
Trigger Threshold:
DC coupled:
Sensitivity: Sinewave - 15mVrms 30Hz to 100MHz, 25mV to 125MHz
AC or DC
1MΩ or 50Ω
1:1 or 5:1
Rising or falling, or width high or low
Filter In (~50kHz cut-off) or Out
Variable thr es hold for both DC and AC coupling
1MΩ//25pF (DC or AC coupled)
< 0.001Hz to >125MHz (1MΩ, DC coupled).
< 30Hz to >125MHz (1MΩ, AC coupled).
0 to 2V (1:1 attenuation) or 0 to 10V (5:1 attenuation).
at optimum threshold adjustment.
Input B
Input Impedance:
Frequency Range: < 80MHz to >3GHz.
Sensitivity: 12mVrms 80MHz to 2GHz, 25mVrms to 2.5GHz, 50mVrms to 3GHz.
Maximum Input Signal: < 0dBm recommended, +13dBm (1V
50Ω nominal (AC coupled).
rms) maximum.
Input C
Input Impedance:
Frequency Range: < 2GHz to >6GHz (typically 1.8GHz to 7.5GHz).
Sensitivity: 25mVrms (–19dBm) 2GHz to 6GHz.
Maximum Input Signal: < +16dBm (1.5Vrms) recommended. Damage level +25dBm (4Vrms).
External Reference Input
Input Impedance:
Frequency: 10MHz.
Signal Level:
TTL, 3V
Ω,
to 5Vpp CMOS or 1 to 2Vrms sinewave.
pp
Maximum Input Voltage
Inputs A, B, C, and
External Reference:
30V
DC; 30Vrms 50/60Hz with respect to earth g r ound
Note that the inputs will not be damaged if subjected t o an accidental short-term connection to a 50/60Hz
line voltage not exceeding 250V
3
rms, or 250V DC.
A Input Frequency Range:
< 0.001Hz (DC coupled) to >125MHz
B input Frequency Range:
80MHz to >3000MHz.
C input Frequency Range:
<2Ghz to >6GHz.
Resolution:
up to 10 digits (see below) or 0.001Hz
A Input Period Range:
8ns to 1000s (DC coupled)
B input Period Range:
0.333ns to 12.5ns
C input Period Range:
0.166ns to 0.5ns
Functions:
Width high or low, ratio H:L (high time to low time) or duty cycle.
Pulse Width Range:
40ns to 1000s
Averaging:
Automatic within measurement time selected, up t o 50 pulses.
averaging. 0.01% for Rat io H:L and Duty Cycle.
Count range:
1 to 9 999 999 999
Minimum pulse width:
8ns
If the ratio exceeds ten digits, displays six digits plus exponent.
Timebase
Measurement Clock: 50MHz.
Internal Reference oscillator: 10MHz TCXO with electronic calibration adjustment.
Oscillator Temperature Stability: Better than ± 1ppm over rated tem per at ur e range.
Initial Oscillator Adjustment Error: < ± 0.2ppm at 21ºC.
Oscillator Ageing Rate: < ± 1ppm first year.
Calibration adjustment range: > ± 8ppm.
Measureme nt Functions
Frequency (Inputs A, B or C)
Period (Inputs A, B or C)
Resolution: up to 10 digits (see below)
Pulse Width Modes (Input A only)
Resolution: 20ns for one pulse; up to 1ns or 10 digits with multiple pulse
Total Count (Input A only)
Frequency Ratio B:A
Resolution: Equal to the resolution of the two f r equency measurements.
Measurement Time
Selectable as 100s, 10s, 1s or 0.3s. The instrument displays the average value of the input
signal over the measurement time selected, updat ed every 2s, 1s, 0.5s or 0.3s respectively. The
hardware captures the count values and continues measuring without any dead time.
Resolution
The displayed resolution depends upon measurement time and input frequency. The basic
resolution of period is 8 digits for every 2 seconds of measurement time. Frequenc y resolution is
the reciprocal of period resolution. Usable resolut ion c an be r educ ed by noise at low frequencies.
Accuracy
Measurement accuracy is timebase accuracy + measurement res olut ion + 2 counts.
4
Operating Facilities
Noise Filter (Input A only)
The Filter key controls a low pass filter, with a cut-off frequency of about 50kHz, to assist in
obtaining stable readings at low frequencies.
Hold
Pressing the Hold key will hold the current measured value in the display, wit h the Hold indicator
on, until the Hold key is pressed again. The measurement cont inues in the bac kground when
Hold is on. A long press on the Hold key clears old data and restarts the meas ur em ent .
Intelligent Power S witching
The unit automatically selects the best available power source of AC adaptor, USB or battery.
Intelligent switching avoids discharging the bat t er y overnight when operated from externally
switched AC power.
A press-to-measure facility allows a quick measurement to be made by pressing a function select
key which will power the instrument up in the corresponding function. The instrument will
automatically switch off 15 seconds after the last k ey-press.
Remote Control
All capabilities can be controlled remotely and measurements read through a USB port.
The instrument can be powered (but the batt er y cannot be c har ged) by the USB host.
Interface: Serial port emulation over USB.
Current consumption: < 100mA (<5mA if AC adaptor power is present)
Command set: Instrument specific. TF830 and TF930 compatible.
Power Re quirements
The instrument has fixed internal rechar geable batteries and is supplied with a universal voltage
external mains adaptor with interchangeable UK, Euro, Australian and US power connectors.
Battery Type: Three 2500mAh NiMH cells.
Battery Operating Life: Typically 24 hour s
Low Battery Indicator: ‘Lo Bat' shows in display when approximately 10% of battery life remains.
Recharge Time: < 4 hours
Adaptor Supply range: 85 to 240V, 50 or 60 Hz,
Power consumption: 5W max at DC input to unit; 15VA max at AC adaptor input (charging).
General
Display: 10 digit LCD, 12.5mm high (0.5”). Annunciators show input
Operating Range: +5° C t o + 40°C, 20% t o 80% RH
configuration, operating mode, measurement units and gate tim e.
Storage Range:
Environmental: Indoor use at altitudes up to 2000m, Pollution Degree 2
Size: 260mm(W) x 88mm(H) x 235mm(D)
Weight: 1050 gms (plus 170 gms AC adaptor)
Electrical Safety: Complies with EN61010-1
EMC: Complies with EN61326
5
–20°C to +60°C
b) EN61000-4-3 (2006) Electromag ne tic Field
Performance levels achieved are detailed in the user manual.
EC Declaration of Conf ormity
We Thurlby Thandar Instruments Ltd
Glebe Road
Huntingdon
Cambridgeshire PE29 7DR
England
declare that the:
TF960 6GHz Universal Counter with USB Interf ace
meets the intent of the EMC Directive 2004/108/EC and the Low Voltage Directive 2006/95/EC.
Compliance was demonstrated by conformance to the following specifications which have been
listed in the Official Journal of the European Comm unit ies.
EMC
Emissions: a) EN61326-1 (2006) Radiated, Class B
Immunity: EN61326-1 (2006) Immunity Table 1, referring to:
a) EN61000-4-2 (2009) Electrostatic Discharg e
Safety – TF960
EN61010-1 Pollution Degree 2.
Safety – A C Power Adaptor
EN60950-1
CHRIS W ILDING
TECHNICAL DIRECTOR
nd
2
October 2012
6
Universal Counter
This instrument has been designed to meet the requirements of the EMC Directive 2004/108/EC.
Compliance was demonstrated by meeting the test limits of t he following standards:
Emissions
EN61326 (2006) EMC product standard for Electrical Equipment for Measurement, Control and
Laboratory Use. Test limits used (radiated emissions only) were Class B.
Immunity
EN61326 (2006) EMC product standard for Electrical Equipment for Measurement, Control and
Laboratory Use. Test methods, limits and performance achieved are shown below (requirement
shown in brackets):
a) EN61000-4-2 (2009) Electrostatic Discharge : 4kV air, 4kV contact, Performance B (B).
b) EN61000-4-3 (2006) Electromagnetic Field:
3V/m, 80% AM at 1kHz, 80MHz – 1GHz: Performance B (A) and 1.4GHz to 2G Hz:
Performance B (A); 1V/m , 2. 0GHz to 2.7GHz: Performance B (A).
Note: The TF960 is a sensitive measuring instrument and, i f subjected to a sufficiently
large RF field, may count its frequency. At lower field strengths a measurem ent might be
disturbed, particularly if the applied signal level is sm a ll. This is much more likely to occur
with the B input than with t he A or C inputs. In all other respects, the instrument will
operate correctly (Perform ance A) in fields up to 3V/m.
EMC
Adaptor/Charger
This AC adaptor/charger has been designed to meet the requirements of the EMC Directive
2004/108/EC.
Compliance was demonstrated by meeting the test limits of t he following standards:
Emissions
EN55022, radiated and conducted Class B.
Immunity
EN55024:1998 + A2:2003. Test methods, limits and performance achieved were:
a) EN61000-4-2 (2009) Electrostatic Discharge : 8k V air, 4kV contact, Perfor m anc e B ( B).
b) EN61000-4-3 (2006) Electromagnetic Field, 3V/m, 80% AM at 1kHz, Performance A (A) .
c) EN61000-4-11 (2004) Voltage Interrupt: ½ cycle and 1 cycle, 0% Perf or m anc e B (B) ;
25 cycles, 70% and 250 cycles, 0% Performance B (C).
d) EN61000-4-4 (2004) Fast Transient, 1kV peak (AC line), Perform ance B ( B) .
e) EN61000-4-5 (2006) Surge, 1kV (line to line), 2kV (line to ground), Perf or m anc e B ( B).
f) EN61000-4-6 (2009) Conducted RF, 3V, 80% AM at 1kHz (AC line only; DC Output
connection <3m, therefor e not tested), Performanc e A (A).
Performance Def initions
The definitions of performance criteria are:
Performance criterion A: ‘During test normal performance within the specification limits. ’
Performance criterion B: ‘During t est, temporary degradation, or loss of function or
performance which is self-recovering’.
7
Universal Counter
This instrument is Safety Class III according to IEC classification and has been desig ned t o meet
the requirements of EN61010-1 (Safety Requirements for Electrical Eq uipment for Measurement,
Control and Laboratory Use).
This instrument has been tested in accordanc e with EN61010-1 and has been supplied in a safe
condition. This instruction manual contains some information and warnings which have to be
followed by the user to ensure safe operation and to r etain the inst r um ent in a safe condition.
This instrument has been designed f or indoor use in a Pollution Degree 2 environment in the
temperature range 5°C to 40° C, 20% - 80% RH (non-condensing). It m ay occasionally be
subjected to temperatures between +5° and -10°C without degradation of its safet y. Do not
operate while condensation is present.
Use of this instrument in a manner not spec ified by these instructions may impair the safet y
protection provided.
All accessible parts will be at the same voltage as the outer of the signal input sockets. In
particular, note that the shell of the USB connector is galvanically connected to the body of the
N-type and BNC inputs and will therefore be at earth ground potential when the USB port is
connected to a desktop PC. However, to maintain user safety under all other circumstances it is
essential that no input is connected to a voltage above 30Vdc or 30Vrms with respect to earth
ground
although the inputs will withstand short-term accidental connection to an AC line voltage up to
250Vrms, 50/60Hz, users will be at risk if the instrument ' ground' is connected to such hazardous
voltages.
which is the limit of Safe Extra Low Voltage (SELV) by IEC definition. Note t hat
Safety
WARNING!
The instrument shall be disconnected fr om all voltage sources before it is opened for any
adjustment, replacement, m aint enance or repair. Any adjustment, maintenance and r epair of the
opened instrument under voltage shall be avoided as far as possible and, if inevitable, shall be
carried out only by a skilled person who is aware of the hazard involved.
Do not wet the instrument when cleaning it.
The following symbols are used on the instrument and in this m anual.
Adaptor/Charger
The adaptor/charger supplied has a universal input voltage rating of 100-240VAC, 50/60Hz. It is
a Class II (double insulated) device, fully approved to EN 60950-1 (2001), UL 60950 (UL listing
E245390).
Direct Current
CAUTION – refer to accompanying documentation.
Damage to the instrument may occur if these precautions are ignored.
meaning that the marked terminal is connected to accessible
conductive parts.
8
Maximum input with respect to earth ground is 30Vdc or 30Vrms 50/60Hz.
Maximum allowable input 1Vrms (1:1 attenuation) or 4Vrms ( 5: 1 attenuation) for
Maximum input with respect to earth ground is 30Vdc or 30Vrms 50/60Hz.
Front Panel Connec tions
Input A
For frequencies in the rang e 0. 001Hz (DC coupled) to > 125MHz. Input im pedance selectable
between 1MΩ//25pF and 50Ω.
1MΩ//25pF input; 1Vrms above 300kHz for 50Ω input ( AC coupled) .
Input B
For frequencies in the rang e < 80MHz to >3GHz. Input impedanc e 50Ω (AC coupled).
Maximum allowable input 1Vrms.
Maximum input with respect to earth ground
Input C
For frequencies in the rang e < 2G Hz to >6GHz. Input impedance 50Ω (250kΩ at DC).
Maximum allowable input 4Vrms.
Maximum input with respect to earth ground
Connections
is 30Vdc or 30Vrms 50/60Hz.
is 30Vdc or 30Vrms 50/60Hz.
EXT REF IN
For a 10MHz signal from an external reference standard only. Input impedance >100kΩ, AC
coupled.
Maximum allowable input TTL, 5Vpp CMOS or 2Vrms sinewave.
Rear Panel Connections
DC IN
DC power to operate and/or recharge the instr um ent is connected via the 1.3mm power socket.
Use ONLY the AC adaptor/charger provided by TTi with the instrument. Use of any other
power source will void the warranty.
USB
The USB port accepts a standard USB cable. The Windows plug-and-play functions should
automatically recognise that the instrum ent has been c onnec ted. The instrument will
automatically be powered by the USB host if the AC adaptor/charger is not connected. USB
power can be used without the USB connection being used for remote cont r ol.
The instrument can only be powered via its USB port if the connection is properly enumerated; it
is therefore not possible to use adaptor s which only provide DC power through a USB connector.
9
Power
The instrument has three possible sources of power: the internal rechargeable battery, DC input
from the AC/DC adaptor/charger supplied (referred to in this manual as t he AC adaptor), or USB
power from a USB host port on a desk-t op or portable PC. The AC adapt or, if present, will be
used in preference to USB power or the battery; without the AC adaptor, USB will take preference
over the battery; only if neither the AC adaptor nor USB power is present will the battery be used.
The instrument software remem ber s t he power-up cause and c ondit ions and acts intellig ent ly at
loss of AC adaptor or USB power to ensure that the battery is not discharged unintentionally.
Power-up and power-down operation for all possible combinations of conditions are detailed in
the sections that follow.
Safety Warning: The TF960 is a safety class III instrument by IEC classif icat ion. When the
instrument is operated from its internal battery, AC adaptor or USB port of a por table
(ungrounded) PC, all accessible parts will be at the same voltage potential as the outer of t he
N-type and BNC input sockets; to maintain user safety it is ther efore essential that no signal input
is connected to a voltage above 30V dc or 30Vrms, the limit of Safe Extra Low Voltage. Note that
although the inputs will withstand accidental short-term connection to an AC line voltage up to
250Vrms, 50/60Hz, users will be at risk if the instrument ‘gr ound’ is connected to such hazardous
voltages.
Manual Operation
Battery Operation
The instrument is fitt ed with rechar geable NiMH cells with a capacity of 2500mAH, giving typically
24 hours use when fully charged. Charging is done using t he AC adaptor supplied, see below.
The Bat annunciator shows in the top right-hand corner of the display when the instrument is
operating from its internal battery; this changes to Lo Bat when approximately 10% of battery
life remains. During battery operat ion t he inst r um ent is turned on and off with alternate presses
of the OPERATE key.
USB Power
The instrument can also be powered from a PC’s host port, even if the instrument’s battery is flat;
the battery will not, however, be recharged from USB power. Connect the instrument’s rear panel
USB connector to a PC via a standard USB cable; the Windows’ plug and play function should
automatically recognise the addition of new hardware and, if this is t he first time the connection
has been made, prompt for the location of a suitable driver. The disk supplied with the
instrument contains drivers for various versions of Windows; follow the PC’s on-screen prompts
to load the appropriate driver (there are two separate stages).
Note: If the plug and play f unction reports that a later version of the dr iver is already installed,
keep the later version; the TF960 will operate satisfactorily with the later version.
The instrument will only be powered via its USB port if the connection is properly enumerated, so
it is not possible to use adaptors which only provide DC power through a USB connector. USB
power takes priority over battery power to preserve battery charge; t he Bat or Lo Bat
annunciator goes off to indicate this.
10
If the instrument is off when the USB connection is enumerated then the instrument will
automatically power on and, when the USB power is removed, it will power off again. If the
instrument is running on battery when the USB connection is enumerat ed t hen USB power will
take precedence in powering the instrument and, when the USB connection is removed, t he
instrument will continue to operate from t he battery. The instrument can be turned off and on with
USB power connected using the OPERATE key. USB power can be used without the USB
connection being used for remote control.
AC A daptor Operation
The AC adaptor is connected to the rear panel 1.3mm socket marked DC IN; only the AC adaptor
supplied with the instrument should be used. When the AC adaptor is powered the red EXT
POW ER lamp will be lit, whether the instrument is on or off; if the battery is being charged the
yellow CHARGING lamp will also be lit. The instrument has intelligent charging control to
optimise performance and battery life plus various protection measures; it is saf e to leave the AC
adaptor connected for long per iods of AC-powered operation though it is always good practice to
disconnect the adaptor from the AC supply and the instrument if the instr um ent is not in use.
The instrument can be turned off and on with the AC adaptor connected using the OPERATE
key. I f the instrument has been tur ned off using the OPERATE key then it will stay off when AC
power is removed and when it is re-applied. If, however, the instrument is off when the AC
adaptor power is applied and had last been powered off by removing the AC power, then the
instrument will automatically power on and, when the AC adaptor power is removed, it will power
off again. This is useful when the instrument is part of a test set-up which is switched on and off
with a mains power mast er s witch.
If the instrument is r unning on battery (or USB power) when the AC adaptor power is applied then
AC adaptor power will take precedence in powering the instrument and, when the AC adaptor
power is removed, the instrument will continue to operate f r om the battery (or USB power). It is
always good practice to disconnect the adaptor fr om t he AC supply and the instrument if the
instrument is not in use for long per iods.
Switching On
The instrument can be switched on and off with alternate press es of the OPERATE key, whatever
power source is being used. At power-on the default operating conditions are always as follows:
Input A, Frequency, AC coupling, 1MΩ input impedance, 1:1 attenuation, rising edg e polar it y, no
filter, 0.3s measurement time and no measurement hold; t he assoc iat ed annunciat or s will show
in the display. The threshold level is set by the position of t he Threshold cont r ol.
If the RESET key is held down whilst the instrument is switched on using the O PERATE key, all
the annunciators will be shown in the display and for 2 seconds the main display area will show
the revision number of the installed firmware. After 2 seconds all the segments of the display will
show as a functional display check until the RESET key is released.
Press to Measure
With the inst r ument off, pressing any of t he m eas ur em ent function switches FREQUENCY,
PERIOD or WI DTH will power up the instrument and set the selected funct ion; all other
conditions are defaulted as described above.
The instrument will then function normally and respond to all k ey presses. After a period of about
15 seconds with no key presses the instrument will automatically power down; this conserves the
battery if operating on battery power.
Input Selection and Configurati on
Inputs A, B or C are selected with successive presses of the INPUT SELECT key; an annunciator
in the display indicates which input is active.
Input A
Input A can be used for frequencies in the range 0. 001Hz to >125MHz and has a number of
configuration options, described below, which allow it to count a wide range of waveform shapes
and amplitudes. The maximum input voltage and onset of clipping will depend on the coupling,
attenuation and input impedance settings and are given in the Specification.
The input is protected against temporary accidental connection of mains voltages up to 250Vrms
at 50/60Hz.
11
Input A Configuration Options
The default configur ation options for Input A at power-on are: AC coupling, 1MΩ input
impedance, 1:1 attenuation, rising edge polarity and no filter; with the Threshold control set to
mid-position a measurement should be possible with the major it y of waveforms. Changes to the
configurations will, however, be necessary for certain waveforms, e.g. DC coupling and low pass
filter in circuit will improve measurement of low frequencies.
Input Coupling: AC coupling is the default and can be used with either input impedance setting.
Select DC coupling for very low frequencies (<30Hz) or if the waveform duty cycle is very low.
DC coupling should normally be used with the input impedance set to 1MΩ; selection of 50Ω is
allowed but, because a 50kΩ protection res ist or is fitted in parallel with the coupling capacitor,
the actual impedance will be much higher than 50Ω until the input frequency is greater than
approximately 300kHz. This configuration can be useful to avoid charging up the coupling
capacitor on asymmetrical waveforms.
When AC coupling is selected the instrument will assume there is no signal and set the display to
0.0 after about 1 second if no tr ans it ion occur s. When DC coupling is select e d it will allow for
very slow signals by waiting forever for an input transition; the display will continue to show the
last value.
Input Impedance: 1MΩ is the default and c an be used with both AC and DC coupling. It can be
used directly or in conjunction with x1, x10 or x100 oscilloscope probes as appropriate to the
signal amplitude. Select 50Ω f or higher frequencies and where the sig nal sour ce im pedance is
50Ω to minimise spurious counting caused by reflections.
Input Attenuation: 1:1 (no attenuation) is the default. Select 5:1 for larger signals, particularly if
noise is significant. When measuring standard logic sig nals, us e 1: 1 at tenuation for 1.8V (or
lower) CMOS and 5:1 for CMOS at 2.5V (or higher), or TTL. Additional attenuation can be
achieved by attenuating the signal externally before being presented to the counter; a x10
oscilloscope probe can be used with the 1MΩ input impedance or a 50Ω attenuator c an be used
with the 50Ω input impedance to preserve matching.
Input Polarity: Rising edge ( pulse Hig h) is the default setting; with this set t ing Frequency and
Period measurements start and finish on the rising edge and Count is the total number of rising
edge occurrences. The Width measurement is from r ising edge to falling edge which, tog ether
with the Period measurement, yields the calculated Ratio (High:Low time) and Duty (Hig h t im e as
a percentage of Period) measurements.
If the Polarity is changed to falling edge (pulse Low), Frequency and Period measurements will
start and finish on the falling edg e and Count will totalise the occurrenc es of falling edges. If the
waveform being measured has a slow rising edge but f ast falling edge, set t ing the Polarity to
falling edge might be advantageous in reducing m eas ur em ent jitter. Changing the Polarity for
Width measurements, however, will change the interpretation of Ratio and Duty and should only
be used with care.
Low Pass Filter: The default set ting is for no filter. If Filter In is selected t he FILT annunciator
will show in the display; the nominal cut-off frequency is 50kHz. The filter is particular ly usef ul for
low frequency measurements but, with an adequate input signal, it can be helpful at freq uencies
up to 200kHz or more.
Trigger Level Threshold Adjustment: The trigger level control is associated with two yellow
LED lamps which indicate the signal balance at the output of the A input am plifier. Their
brightness varies from brig ht to dim depending on the relationship between the trig ger threshold
and the average value of the input signal. When the threshold sett ing matches the average value
of the input signal they are of equal brightness. If a signal is applied and the instrument is not
counting, move the threshold control towards t he dimm er of the two lamps. Note that the smaller
the input signal level, the more critical this setting becomes.
12
When AC coupling is selected (the default config ur at ion) a t hreshold feedback mechanism is
engaged, with the threshold control providing a small offset above or below the average signal
level. Normally the control should be set with the marker at the m idway position marked AC.
This setting should count most signals, but on very small signals some slight adjust m ent m ay be
needed for maximum sensitivity. The usable adjustment range from this position is approximately
±50mV (1:1 attenuation) or ± 200m V ( 5: 1 at tenuation).
If DC coupling is in use then the feedback mechanism is disconnected and the threshold is
directly adjusted by the control over the range of nom inally 0 t o 2V ( 1: 1 at tenuation) or 0 to10V
(5:1 attenuation).
There is some over-range at each end of the control. The Threshold control should be adjusted in
the direction which brings both yellow LED lamps on and then finely adjusted to get the most
stable measurement.
For waveforms with slow edges adjusting the threshold will, of course, affect the Width and
associated Ratio and Duty cycle measurements but not Frequency, Period and Count.
The Threshold control should always be adjusted slowly, as there is a noise rejection filter with a
long time constant in the circuit.
Input B
Input B is used for frequency measurements in the range 80MHz to >3GHz. The input
impedance is nominally 50Ω. The maximum input voltage from 20MHz to 3GHz is 1Vrms and the
input is diode clipped with inputs over 250mVrms.
The input is protected against temporary accidental connection of mains voltages up to 250Vrms
at 50/60Hz.
The signal being measured should have a 50Ω sour c e impedanc e t o avoid standing waves which
could give spurious results. The input cable should be kept as short as possible and 50Ω coaxial
cable should be used.
Note that, because of the wide bandwidth of this input, signals m ixed with other components
which fall within the frequency and sensitivity range of the input can cause incor r ec t c ount ing;
externally attenuating or filtering t he signal before presenting it to the counter may help to obtain
a correct reading. In particular, when attempting to count the highes t frequency component of a
signal with broadband noise or other interference, an exter nal hig h pass filter may be needed,
especially with small signals above 2GHz. The C input provides better performance above this
frequency.
Input C
Input C is used for frequency measurements in the range 2GHz to >6GHz. Although the
sensitivity is not specified outside this range, it will typically count frequencies f r om 1. 8GHz up to
7.5GHz. The input impedance is nominally 50Ω. An input coupling capacitor is followed by a
resistive attenuator and a PIN diode limiter. The maximum input voltage for correct counting is
1.5Vrms (+16dBm) and the maximum input without damage is 4Vrms (+25dBm). There is a
250kΩ DC coupled bleed resistor to minimise t he r isk of static build up destroying the input
coupling capacitor. This input is also protected against temporary accidental connection of mains
voltages up to 250Vrms at 50/60Hz.
The signal being measured should have a 50Ω sour c e impedanc e t o avoid standing waves which
could give spurious results. The input cable should be kept as short as possible and 50Ω coaxial
cable should be used.
This input has a sharp low frequency cut off below 1.5GHz and has much better noise immunity
than the B input. It also has much better large signal handling capabilities. Unless the Ratio B:A
capability is needed the C input should be preferred for all signals above 2GHz.
Function and Measurement Time Selection
Function and measurement time are selected using the keys immediately below the display. The
annunciators in the display show the current settings.
Function Selection – A input
Pressing the FREQUENCY, PERIOD or WIDTH key will immediately set the instrument to that
function; pressing and holding the key down for more than 1 second will change the function t o
13
COUNT, RATIO or DUTY respectively, the 2nd function printed above the key in blue; the selected
function is shown by the appropriate annunciator in the display.
FREQUENCY and PERIOD measurements are directly displayed in the appropriate units.
COUNT is a simple totalise function. The displayed value can be frozen with the HOLD key; the
count continues in the background. The count can be restarted (set to zero) using RESET, the 2
function of HOLD. When the count reaches the maximum of 9999999999, the next active edge
restarts the count from zero.
The WI DTH measurement can be set to measur e either the High time (above the threshold) or
Low time (below the threshold) by choosing the appropriate polarity setting, s ee ear lier Input A
Configuration Options section.
Selecting RATIO with the A input active shows the ratio of Hig h time to Low time (RATIO H:L) or
vice-versa, according t o t he polar it y sett ing. Low (inactive) time is calculated by subtracting the
measured High (active) time fr om the period.
Selecting DUTY shows the High time or Low time (depending on polarity setting) expressed as a
percentage of the total period.
Function Selection – B input
With Input B ( 80MHz – 3GHz) selected only the FREQUENCY and PERIOD functions can be
used; attempts to select WIDTH, COUNT or DUTY will be ignored by the firmware; the
annunciator will flash briefly to indicate that this is not a valid selection and the existing setting will
remain unchanged.
Selecting RATIO with Input B selected (by a long press on the PERIO D key) is valid, but sets the
instrument to a RATIO B:A mode (Frequency B : Frequency A), not RATIO H:L as described for
the A input. The ratio B:A is obtained by making simultaneous frequency measurements on the
two inputs and dividing the B result by the A result. The result of the calculat ion is as accur ate as
the measurements. Each signal can be any frequency within the permitted range of the
respective input. If the ratio is so lar ge that the decimal point cannot be shown on the display,
then the result is shown with six digits and an exponent.
B
nd
Function Selection – C input
With Input C ( 2G Hz – 6GHz) selected only the FREQUENCY and PERIOD functions can be
used; attemp ts to select WIDTH, CO UNT, RATIO or DUTY will be ignored by the firmware; the
annunciator will flash briefly to indicate that this is not a valid selection and the existing setting will
remain unchanged. There is no RATIO capability wit h either of the other inputs.
Measurement Time
Measurement time is changed using the left ◄ and right ► MEASUREMENT TIME keys, the
selected time being shown by the appropriate annunciator in the display. With a suitable signal
connected to the selected input the Measure annunciator will flash in the display to indicate that
the signal has been detected; the Measure annunciator cont inues to flash until a true result f or
that selected measurement time is displayed, at which point it stays on continuously. Further
display updates then show the running average of the signal behaviour over the last 0. 3s (1
update every measurement), 1s (2 updates per sec ond) , 10s ( 1 updat e per second) or 100s (1
update every 2 seconds) depending on the selected measurement t im e. Not e t hat if a 1s, 10s or
100s measurement time is selected, starting or restarting a measurem ent gives a true result with,
generally, 7 digits resolution after 0.3s, 8 digits aft er 1s , 9 digits after 10s and, finally, 10 digits
after 100s. The units and the decimal point position are automatically adjusted t o give the result
in the most convenient units.
Pressing the HOLD key will freeze the displayed measurement and the Hold annunciator will
be shown; Hold is cancelled by a second press of the HOLD key. The measurement continues in
the background while Hold is selected.
C
14
Switching between FREQUENCY and PERIOD measurement on the same input, or switching
between WIDTH, RATIO H:L and DUTY (Input A), will immediately convert the present
measurement; otherwise, a change of function (including a change of input) or measurement
time will initiate a new measurement. A new measurement may also be started without a change
of function or measurement time by using RESET, the 2
Measurement Principles
Frequency and Period
The instrument uses a measurement method generally known as reciprocal counting. After each
measurement interval (gate time) ends , it waits for t he c om plet ion of the present cycle of the
input signal before capturing t he c ount data. I t has t her efore measured the time tak en by a whole
number of input cycles with a resolution of one cycle of its internal m easur em ent clock. It then
calculates the average period of the input sig nal by dividing the total time by the number of input
cycles; the frequency is the reciprocal of this period value. This method yields much more
accurate results at low frequencies than the traditional method of counting input c ycles f or an
exact gate time.
The hardware captures count values without either stopping or r eset ting the counters. This is
known as “capture and continue” counting, and m eans t her e is no dead t im e at the end of each
gate interval. This allows successive measurements to be concatenated without incurring a one
clock cycle uncertainty at the intermediate points of the m eas ur em ent . The instrument uses this
capability to give a rolling update in the display more often than the selected gate t im e. Each of
these updates show the average value of the input frequency over the time interval equal to the
selected gate time immediately preceding it being di splayed.
nd
function of the HOLD key.
If the signal has fr equency modulation the instrument will display the average value across the
gate time; the modulation is almost c er tainly not synchronous with the gat e, so there will be small
random variations in the displayed value.
If the signal has amplitude modulation, its amplitude at the trough of the modulat ion m ust exceed
the sensitivity threshold of the input. Counting deeply modulated sig nals r equires both
considerable amplitude and a sensitive adjustment of t he t r igger threshold.
Width, Duty Cycle and Ratio H:L Measurements
When Width mode is selected, the instr um ent continues to use the capture and continue met hod
to measure the signal period. It c annot m eas ur e t he width of t he active part of the signal this way
because, by definition, there are gaps between the measur em ents while the signal is in the
inactive state. Instead, it measures the width of a sam ple of individual cycles of the input signal at
a rate up to about 1000 samples per second. It ac cum ulat es up t o 50 suc h sam ples spread
across the selected gate time, com putes the average and displays the result. Each sample has a
resolution of 20ns, and the average is displayed with a resolution up to 1ns. The values for duty
cycle and ratio H:L (better thought of as the rat io act ive:inact ive) are computed from the average
width and the accurately known period. The display resolution presented in these modes is a
reasonable representation of the probable measurement accuracy.
Ratio B:A
This mode is entered by a long press of t he WIDTH / RATIO key when the B input is selected. It
takes as nearly simultaneous capture and continue measurements of bot h input signals as
possible. Because each measurement terminates on a t r ans ition of its respective signal the two
measurements are not exactly simultaneous unless the signals are synchronously related. This is
not likely to be an issue unless the signals are significant ly f r equency modulated.
Note that this method is completely different to the previous model (the TF830) which
implemented ratio B:A mode by counting the B input using the A signal as the reference
timebase.
15
Timebase and Other Accuracy Considerations
The following is intended as a guide to determine the limits of measurement error.
Internal Oscillator
The instrument has an internal temper ature compensated crystal oscillator (TCXO) which has
been factory set from a Rubidium reference standard such that it is within ± 0.2ppm (parts per
million) after warm-up in an ambient of 21ºC. At ambient temperatures other than 21ºC the
additional error is less than ± 1ppm over the whole operating rang e 5º C t o 40º C.
The ageing rate is less than ± 1ppm in t he first year and decreases exponentially with time. The
recommended calibration period is 1 year, see Maintenance section.
External Reference
If measurements are to be m ade which requir e st ill g r eat er ac cur ac y than can be obtained using
the TCXO, an external 10MHz frequency standard may be applied to the External Reference
input. The signal should be TTL, 3Vpp to 5Vpp CMOS or 1 to 2Vrms sinewave. The external
reference is used to phase lock the int er nal osc illator and must only be a high accuracy 10MHz
signal. It is not possible to make r atiometric measurements by applying a non-standard signal.
The presence of an external ref er ence s ig nal of adequate amplitude is automatically detected
and phase lock is attempted; the Ext Ref display annunciator is shown when the external
reference is detected. Note t hat if an improper signal is applied then the internal oscillator will be
pulled off frequency and measurement accuracy significantly impaired.
Noise
When measur ing low amplitude, low fr equency sinewaves noise will cause variations in the
displayed result at each display update. Users should make every effort to maximise the
amplitude of the signal presented to the input. The internal noise of the instrument is r andom ,
with a significant low frequency (1/f) element. Selecting a longer gat e time will reduce the effect
of this noise, and allow the user to see the extremes of the variation and establish an
approximate average. This method may be less effective on signals with externally induced
intermittent or non-random noise ( suc h as supply f requency interference).
Signal level
In general it is obvious from the variations of the display value that a signal is too small for
reliable counting, but on the B input at f r equencies over about 2GHz and on the C input at
frequencies over about 5GHz the effect of insufficient signal can be very subtle. A sig nal 2 or 3dB
below the true threshold might only show an error in the eighth digit in a consist ent way that is
not obviously detectable; for true accuracy users are recom m ended to ensure that the signal
level meets the published specification even though the instrument is typically notably more
sensitive.
16
The USB interface allows the instrument to be cont r olled using serial communications via a
computer’s USB port.
The instrument is supplied with a disk containing drivers for various versions of Windows. Any
driver updates are available via the TTi website, www.tti-test.com. The disk also contains a t ext
file with information and details of the soft ware installation procedure.
The remote command f or m at and the remote commands themselves are detailed later in this
section. The remote commands of the earlier TTi TF830 Universal Counter can also be used on
the TF960, allowing existing programs to be used. However, the TF960 has no address
capability and those commands associated with ARC (Addressable RS232 Control) will be
accepted but ignored.
Remote/Local Operation
At power−on the instrument will be in the local state; in this state all keyboard operations are
possible. When the inst r ument receives a command the remote state will be entered and the
Rem annunciator will show in the display. In this state the keyboard is locked out, except for the
Local (RESET) and OPERATE keys, and remote commands only will be processed.
The instrument may be returned to the local state by a long press of the Local (RESET) k ey; t he
Rem annunciator will go off. However, the effect of this action will remain only until the
instrument receives another character from the interfac e, when the rem ote state will once again
be entered. Sending the LOCAL command also exits the remote state.
Remote Operation
USB Interface
The USB interface of this inst r um ent is implemented using a USB to UART device which then
communicates with a UART inside the main processor. Once the device drivers are installed on a
PC the device will appear to be a standard COM port as if it were inside the PC. This port can
then be accessed by Windows applications in exactly the same way as a standard port.
If it is anticipated that more than one TF960 mig ht be connec t ed to the same PC it is
recommended that the drivers be copied fir st to a suitable location on the hard disc and then
installed from there when the first unit is at tached. The operating system can then subsequently
find the drivers without requiring the CD.
Installation of the interface dr ivers is achieved by connecting the inst rument to a PC via a
standard USB cable. The Windows’ plug and play functions should automatically recognise the
addition of new hardware attached to the USB interface and, if this is the first time the connect ion
has been made, prompt for t he locat ion of a suitable driver. Two layers of driver are required and
the standard Windows prompts will appear twice. Provided that these prom pts ar e followed
correctly Windows will install the appropriate drivers and establish a COM port within the PC. The
number of the new COM port will depend upon the number of previously allocated COM ports
within that PC.
Note: If the plug and play f unction reports that a later version of the dr iver is already installed,
keep the later version; the TF960 will operate satisfactorily with the later version.
A unique code embedded in each instrument ensures that it will receive the same COM port
number each time it is attached to the PC, irrespec t ive of which physical USB port it is connected
to. A different unit will prompt ag ain for installation of the drivers the first time it is attached, and
will receive a different COM port number.
The operating parameters of the COM port must be set to match the int er nal r equirements of the
instrument: baud rate 115200, 8 bits, no parity. The default values are set in the Properties page
in Device Manager, but many communications programs override the default settings and each
will need to be correctly configured.
17
<rmt>
<RESPONSE MESSAGE TERMINATOR>
<c>
A single character, either a digit or a letter.
<nr1>
An integer number.
0 B Input Period
1 A Input Period
2 A Input Frequency
3 B Input Frequency
4
Frequency Ratio B:A
5 A Input Width High
6 A Input Width Low
7 A Input Count
8
A Input Ratio H:L
9 A Input Duty Cycle
C C Input Frequency
D C Input Period
The new function is selected immediately and a new measurement is started.
Remote Command Format
Serial input to the instrument is buffered in an input queue which is filled, under interrupt, in a
manner transparent to all other instrum ent oper ations. The instrument will send XOFF when the
queue is nearly full; XON will be subsequently be sent when sufficient space becomes available
for more data to be received. This queue contains raw (un−parsed) data which is taken, by the
parser, as required. Commands (and queries) are executed in order and the parser will not start a
new command until any previous command or query is complete. Responses to commands or
queries are sent immediately; there is no output queue.
Commands must be sent as specified in the com m ands list and m us t be terminated with the
command terminator code 0AH (Line Feed, LF). Com m ands m ay be sent in groups with
individual commands separated from each other by the code 3BH (;). The gr oup must be
terminated with command terminator 0AH (Line Feed, LF) .
Responses from the instrument to the controller are sent as specif ied in the com mands list. Each
response is terminated by the
followed by 0AH (Line Feed, LF).
<WHITE SPACE> is defined as character codes 00H to 20H inclusive with the exception of the LF
character (0AH).
equivalent to '*IDN?'. The high bit of all characters is ignored. The commands are case
insensitive.
Each query produces a specific
remote commands list.
<WHITE SPACE> is ignored except in com m and ident ifiers. e.g. '*I DN?' is not
<RESPONSE MESSAGE TERMINATOR> 0DH (Carriage Return, CR)
<RESPONSE MESSAGE> which is listed with the command in the
Command List
This section lists all commands and queries implemented in t his inst r um ent . The commands of
the TF830, all of which have been implemented on this instrument, are identif ied by “T F830” on
the right-hand side of the Remot e Com m and Sum m ar y list (next sec t ion) .
Each command is completely executed before the next comm and is s tart ed.
The following nomenclature is used:
Function Selection
F<c>
Sets the measurement function to < c > , where c cor r esponds t o t he following:
18
AC
Set A Input to AC coupling.
DC
Set A Input to DC coupling.
Z1
Set A Input to 1MΩ input impedance.
Z5
Set A Input to 50Ω input impedance.
A1
Set A Input to 1:1 att enuat ion.
A5
Set A Input to 5:1 att enuat ion.
ER
Set rising edge of waveform as start of measurement.
EF
Set falling edge of waveform as s tart of measurement.
FI
Low Pass Filter In (on).
FO
Low Pass Filter Out (off).
remote state is cleared the filter setting remains as it was in the remote state.
to +60; if no sign is present, < nr 1> is ass um ed t o be pos it ive.
sign is negative.
the range -300 to +2100; if no sign is present, <nr1> is assumed to be posit ive.
sign is negative.
will be the set value x 5.
automatically adjusts to the average level of the waveform being m eas ur ed ( no offset).
L
When remote state is first entered the filter stays set as it was in the local state. When
Low frequency mode. Applicable to TF830 only. Command accepted but ignored by TF960,
which is automat ically in low frequency mode while DC coupling is selected.
Threshold Commands
TO <nr1>
TO? Returns the current TO Threshold value in the form SnnnnmV<r m t>, where S is the sign,
TT <nr1>
TT? Returns the current TT Threshold value in the form Snnnnm V<rmt>, where S is the sign,
Values f or TT and TO assume an input attenuation setting of 1:1; for 5:1 at t enuat ion t he effective levels
TA
Use with AC coupling. Threshold automatically adjusts to the average level of the
waveform being measured, offset by <nr1> m V, where <nr1> is a number in the range -60
nnnn is the Threshold voltage in mV and mV is the units specifier. S is only present if the
Use with DC coupling. Threshold set to a level of <nr1> mV, where <nr1> is a number in
nnnn is the Threshold voltage in mV and mV is the units specifier. S is only present if the
Use with DC coupling. Threshold Level set to achieve auto triggering; the thr es hold
In all cases the threshold level is set irrespective of the posit ion of the front panel control. When remote
state is first entered the trigger level is exactly as it had been set from the front panel (the TO? or TT?
command can be used to read this value, corresponding t o whether AC or DC coupling is currently set).
When the remote state is cleared the trigger level reverts to the s et ting determined by the current f r ont
panel control position. Note that although mV resolution is provided, offsets within the instrument result
in the actual value being only approximately correct. It is accurate enoug h t o allow the sett ing of
standard logic thresholds, but if maximum s ensit ivity to small signals is r equired when DC coupled then
some experiment may be required.
Using TO <nr1> with DC coupling or TT <nr 1> with AC coupling may give unpredictable results; it is up
to the user to use settings cons ist ent with each other and with the m easur ement application.
TA requires the user t o first set DC coupling; TA can be useful for autom at ically finding a us eable
measurement threshold for low fr equency waveforms that require DC coupling, or for higher freq uenc y
waveforms with very small duty cycles. There is no equivalent front panel setting.
19
TC
TN
TP
ter. ‘Centre’ is
on the TF830).
M<c>
Sets the measurement time to <c>, where c cor r esponds t o the following:
1 0.3s
2 1s 3
10s
4 100s
The new measurement time is selected immediately and a new measurement is start ed.
all results will be valid measurements. Stopped by <STOP> or any other command.
be valid. Stopped by <STOP> or any other command.
annunciator is not flashing, i.e. the next valid measurement.
<Measure> annunciator was flashing or not, i.e. t he measurement may not be valid.
where:
characters).
e is the letter e for exponent.
S is a plus or minus sign indicating the sign of the exponent.
E is the exponent value to give the answer in Hz or seconds
0000000000.e+0_ _<rmt>
command.
Threshold Level to centre position.
Threshold Level to negative pulse position.
Threshold Level to positive pulse position.
These three commands are only included to maintain compatibility with the TF830 and are used to set the
threshold level to one of three ‘preset’ positions available under remote control on that coun
equivalent to the threshold level control at the midway 'AC' position. ‘Negative pulse’ and ‘positive pulse’
are equivalent to –60mV and +60mV respectively, with AC coupling selected (the only coupling available
Measurement Commands
E?
Every Result Query. Measurement r esults are sent continuously at the interval set for t he
measurement time (0.3s, 1s , 10s or 100s). Since these are ‘measurement t ime’ intervals,
C?
Continuous Result Query. Measurement results are sent continuously at the rate at which
the LCD is updated for the selected measurem ent time – every 2s, 1s, 0.5s or 0.3s for
measurement times of 100s, 10s , 1s or 0. 3s r espec t ively. Measurements are sent
whether the <Measure> annunciator was flashing or not, i.e. the measurement may not
N?
?
Next Result Query. The measur em ent at the next LCD update provided the <Measure>
Current Result Query. The measurem ent at the most recent LCD update whether the
The format of the response is the same for all f or m s of the query and is as follows:
NNNNNNN.NNNeSEuu<rmt>
NN.NN is the displayed answer with the decimal point in the corresponding posit ion (11
uu is the units specifier: Hz, s_ , %_ or _ _ ; _ is a space (2 characters)
If there is nothing to m eas ur e and t he display is zero the response will be:
STOP
Stops further measurements being sent in response to E? or C?; any other command will
also stop further measurem ents being s ent , as well as initiating the action of that
20
<version> is the revision of the firmware installed.
I?
Identify Query. Returns the instrument model number only.
midway ‘AC' position. Also em pt ies r em ote I/O queues and clears error s tatus .
key under the same conditions.
7. The meaning of each bit is as follows:
cleared to zero after each status query. Error numbers are as follows:
command. Examples of use are Serial No., calibration due date, owner’s name, etc.
UD?
Returns user data from store.
F0
B Input period.
F1
A Input period.
TF830
F2
A Input frequency.
TF830
F3
B Input frequency.
TF830
F4
Frequency ratio B:A.
TF830
F5
A Input widt h Hig h.
TF830
F6
A Input widt h Low.
TF830
F7
A Input count.
TF830
F8
A Input ratio H:L.
F9
A Input duty cycle.
FC
C Input frequency
FD
C Input period
Miscellaneous Commands
*IDN?
*RST
R
S?
Returns the instrument identif icat ion in the form <name>, <model> , 0, < version>< rmt>
where <name> is the manufacturer’s name, <model> is the type of instrument and
Resets the instrument to its power-on default values and sets the Threshold Level to the
Reset measurement. Perf or m s the same operation as pressing the front panel RESET
Status Query. Reads and returns the instrument status. The response is sent
immediately. The response is xy<rmt > , where x and y are numeric digits expressed in
ASCII format. The first digit is the status byte and is a bit significant value in the rang e 0 to
bit 0 External standard connected.
bit 1 An error has occurred.
bit 2 A continuously updated bit indicating that an input signal is being counted. It does
not necessarily guarantee that there is sufficient signal for an accurate r esult .
The second byte contains the error number of t he last error that occurred. The value is
0 No error has occurred since the last status q uery.
1 A command syntax error – one or more commands ignored.
LOCAL
UD <data>
Returns the instrument to local operation and unlocks the keyboard.
Store user data; maximum string length 250 characters. The string may contain any
character between 20H and FFH inclusive except 3BH (;). Can be used to give the
instrument an identifying or inf or m ation data string which can be queried using the UD?
Remote Command Summary
The commands of the TF830, all of which have been implemented on this instr um ent, are identified by
“TF830” on the right-hand side.
21
AC
A input AC coupled.
DC
A input DC coupled.
Z1
A input 1MΩ input impedance.
Z5
A input 50Ω input impedance.
A1
A input 1:1 attenuator.
A5
A input 5:1 attenuator.
ER
Rising edge (A Input only).
EF
Falling edge (A Input only).
FI
Filter In (A Input only).
TF830
FO
Filter Out (A Input only).
TF830
L
Low frequency mode.
TF830
DC coupling.
AC coupling.
Values assume 1: 1 attenuator; for 5: 1 at tenuation thresholds will be set value x5.
TO?
Returns current TO Threshold setting in mV
TT?
Returns current TT Threshold setting in mV
TA
Trigger auto (average, without offset) . Set DC coupling first.
TC
Trigger centre.
TF830
TP
Trigger positive.
TF830
TN
Trigger negative.
TF830
M1
Measurement time 0.3s.
TF830
M2
Measurement time 1s.
TF830
M3
Measurement time 10s.
TF830
M4
Measurement time 100s.
E?
Every result query.
TF830
C?
Continuous result query.
N?
Next result query.
TF830
?
Current result query.
TF830
STOP
Stops further measurement results being sent.
I?
Identifier query. Returns model number only.
TF830
*IDN?
Instrument identification. Ret ur ns full instrument identification.
R Reset measurement.
TF830
*RST
Reset instrument to default s et t ings.
S?
Status query.
TF830
LOCAL
Returns instrument to local operation.
UD <data>
Store user data.
UD?
Returns <data>.
TT <nr1>
TO <nr1>
Trigger threshold set to nnnn mV (-300 to + 2100mV).
Trigger auto (average), offset by nn mV ( -60 to +60mV).
22
The Manufacturers or their ag ents overseas will provide a repair service for any unit developing a
fault. Where owners wish to undertake their own maintenance work, this should only be done by
skilled personnel in conjunction with the Service Information available from the Manufacturers or
their agents overseas.
Calibration
Calibration at the time of delivery is guaranteed as in the Specification. However, annual routine
recalibration is recommended to maintain the high accurac y that t his inst r um ent offers.
Recalibration may be carried out, without dismantling the instrum ent, using a suitable precision
frequency standard; details are provided in the Service Information.
Cleaning
If the instrument r equires cleaning use a cloth that is only lightly dampened with water or a mild
detergent.
WARNING! TO AVOID ELECTRIC SHOCK, OR DAMAGE TO THE INSTRUMENT, NEVER
ALLOW WATER TO GET INSIDE THE CASE. TO AVOID DAMAGE TO THE CASE OR
DISPLAY WINDOW NEVER CLEAN WITH SOLVENTS.
Maintenance
23
Ltd
.
)
Thurlby Thandar Instruments
Glebe Road • Huntingdon • Cambridgeshire • PE29 7DR • England (United Kingdom
Telephone: +44 (0)1480 412451 • Fax: +44 (0)1480 450409
International web site:
www
.aimt t i.com • UK web site:
www
.aimt t i.co.uk
Email: info@aimt t i.com
Aim Instruments and Thurlby Thandar Instruments Book Part No. 48581-1440 Issue 2
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