TF930 3GHz Universal Counter INSTRUCTION MANUAL
Table of Contents Introduction 1 Specification 2 Safety 5 Connections 6 Manual Operation 7 Remote Operation 14 Maintenance 20 Introduction The TF930 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 3GHz and measurement functions include frequency, period, ratio, pulse width and count.
Specification Input Specifications Input A Configurable options Input coupling: Input impedance: Attenuation: Active edge: Low pass filter: Trigger threshold: Input Impedance: Frequency Range: Trigger Threshold: DC coupled: AC coupled: Sensitivity: 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 threshold for both DC and AC coupling 1MΩ//25pF (DC or AC coupled) or 50Ω nominal (AC coupled only). < 0.001Hz to >125MHz (1MΩ, DC coupled).
Timebase Measurement Clock: 50MHz. Internal Reference oscillator: 10MHz TCXO with electronic calibration adjustment. Oscillator Temperature Stability: Better than ± 1ppm over rated temperature range. Initial Oscillator Adjustment Error: < ± 0.2ppm at 21ºC. Oscillator Ageing Rate: < ± 1ppm first year. Calibration adjustment range: > ± 8ppm. Measurement Functions Frequency (Input A or Input B) A Input Frequency Range: < 0.001Hz (DC coupled) to >125MHz B input Frequency Range: 80MHz to >3000MHz.
Operating Facilities Noise Filter 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, with the Hold indicator on, until the Hold key is pressed again. The measurement continues in the background when Hold is on. A long press on the Hold key clears old data and restarts the measurement.
Safety Universal Counter This instrument is Safety Class III according to IEC classification and has been designed to meet the requirements of EN61010-1 (Safety Requirements for Electrical Equipment for Measurement, Control and Laboratory Use). This instrument has been tested in accordance with EN61010-1 and has been supplied in a safe condition.
Connections Front Panel Connections Input A For frequencies in the range 0.001Hz (DC coupled) to >125MHz. Input impedance selectable between 1MΩ//25pF and 50Ω. Maximum allowable input 1Vrms (1:1 attenuation) or 4Vrms (5:1 attenuation) for 1MΩ//25pF input; 1Vrms above 300kHz for 50Ω input (AC coupled). Maximum input with respect to earth ground is 30Vdc or 30Vrms 50/60Hz. Input B For frequencies in the range <80MHz to >3GHz. Input impedance 50Ω. Maximum allowable input 1Vrms.
Manual Operation 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 the AC adaptor), or USB power from a USB host port on a desk-top or portable PC. The AC adaptor, 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.
AC Adaptor 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 POWER 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.
Input A Configuration Options The default configuration 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 majority 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.
This setting should count most signals, but on very small signals some slight adjustment may be needed for maximum sensitivity. The usable adjustment range from this position is approximately ±50mV (1:1 attenuation) or ±200mV (5:1 attenuation). 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 nominally 0 to 2V (1:1 attenuation) or 0 to10V (5:1 attenuation). There is some over-range at each end of the control.
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 B annunciator will flash briefly to indicate that this is not a valid selection and the existing setting will remain unchanged.
If the signal has frequency modulation the instrument will display the average value across the gate time; the modulation is almost certainly not synchronous with the gate, so there will be small random variations in the displayed value. If the signal has amplitude modulation, its amplitude at the trough of the modulation must exceed the sensitivity threshold of the input. Counting deeply modulated signals requires both considerable amplitude and a sensitive adjustment of the trigger threshold.
Noise When measuring low amplitude, low frequency 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 random, with a significant low frequency (1/f) element. Selecting a longer gate time will reduce the effect of this noise, and allow the user to see the extremes of the variation and establish an approximate average.
Remote Operation The USB interface allows the instrument to be controlled 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, http://www.aimtti.com/support. The disk also contains a text file with information and details of the software installation procedure. The remote command format and the remote commands themselves are detailed later in this section.
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 instrument operations. 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.
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 attenuation. A5 Set A Input to 5:1 attenuation. ER Set rising edge of waveform as start of measurement. EF Set falling edge of waveform as start of measurement. FI Low Pass Filter In (on). FO Low Pass Filter Out (off). When remote state is first entered the filter stays set as it was in the local state.
TC Threshold Level to centre position. TN Threshold Level to negative pulse position. TP 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 counter. ‘Centre’ is equivalent to the threshold level control at the midway 'AC' position.
Miscellaneous Commands *IDN? Returns the instrument identification in the form , , 0, where is the manufacturer’s name, is the type of instrument and is the revision of the firmware installed. I? Identify Query. Returns the instrument model number only. *RST Resets the instrument to its power-on default values and sets the Threshold Level to the midway ‘AC' position. Also empties remote I/O queues and clears error status. R Reset measurement.
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 TT Trigger threshold set to nnnn mV (-300 to +2100mV). DC coupling. TO Trigger auto (average), offset by nn mV (-60 to +60mV). AC coupling.
Maintenance The Manufacturers or their agents 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.
Thurlby Thandar Instruments Ltd. Glebe Road • Huntingdon • Cambridgeshire • PE29 7DR • England (United Kingdom) Telephone: +44 (0)1480 412451 • Fax: +44 (0)1480 450409 International web site: www.aimtti.com • UK web site: www.aimtti.co.uk Email: info@aimtti.com Aim Instruments and Thurlby Thandar Instruments Book Part No.
