tinydevices.org | TinyGTC / tinyGTC home page
View
Edit
History
TinyGTC /
tinyGTC home page
What is the tinyGTC?
The tinyGTC is a dual Timer/Counter with built-in GPSDO with up to two clock outputs, it is a portable, battery operated, five SMA connectors, one USB connector device with a 4 inch display. It has a on/off switch, a jog wheel for when there is a problem with display touch and a SD card slot.
What is in the box?
The tinyGTC comes together with an active GPS antenna, short USB cable, two 30 cm coax cables and SMA Tee.
WARNING : Due to its small size and low cost the tinyGTC is not as well protected against overloading as larger, more expensive counters. Please do read this how not to damage your tinyGTC guide
SMA connectors from left to right
OUT (output): Is the main AC coupled clock output. Can output frequencies between 0.1 Hz and 150 MHz
REF (input/output): Can be used as an AC coupled input for an external 10MHz reference clock, or as a secondary clock output between 8 kHz and 250 MHz.
GNSS (input): For connecting an active GPS antenna using the internally generated 3.3 V bias.
Input A (input): This DC coupled input can be used for input frequencies between 0.1 Hz and 350 MHz or, when using the GHz prescaler, up to 7 or 12 GHz
Input B (input): Is identical to Input A input except for not having the GHz prescaler function.
WARNING : exceeding the safe input levels on any of the inputs can quickly destroy your device, Please do read this how not to damage your tinyGTC
The status of each input is visible in the Input/Counter field [3] and [4]
The tinyGTC has two independent high resolution counter/timers that can measure frequency, phase, count or time where there is no limit to the time between events. Time is measured with 40 ps resolution and the measurement interval can be set between 1ms and 10 seconds. Frequencies and phase are measured using gapless interpolated reciprocal counting providing input frequency independent accuracy of 1e-11 to 1e-12 per second measurement time.
Each counter/timer can use one of a number of sources:
Counter sources
A Input
B input
REF input/output
There is a third internal counter/timer with 4 ns measurement resolution dedicated to measuring the GPS PPS as input to the GPSDO
The status of each counter is visible in the Input/Counter fields (see UI fields [4])
Measurement results can be displayed on up to 5 numeric measurement rows (see UI rows [5]) in a selectable formats such as frequency, period or time and each display line can select one of the following sources:
Data sources
CNTR 1 counter 1 using input A by default
CNTR 2 counter 2 using input B by default
TIME time/date with 1 second accuracy
LOCK ERROR estimated frequency/phase error of the GPSDO
LOAD cpu load in percentage, same as displayed in the System field at the top left of the display
GPS PPS counter 3 measuring the GNSS PPS
VBAT the voltage of the internal rechargeable battery
The selected input is displayed at the top of each measurement row
Each row can have up to three buttons:
STOP/START stops or starts continuous measurements
SINGLE performs a single measurement ending in the STOP state. Click START to restart continuous measurements
RESTART shown when statistics are being measured. Resets the statistics and the plot
The first 4 measurement rows can optionally be shown in a graph versus time where the graph shows maximum 400 measurements. When the graph is full the graph will either scroll horizontally or it will be compressed forever while showing maximum and minimum or an averaged measurement for each displayed compressed time interval. The accumulated data of up to 3000 measurements can also be shown using a transform such as histogram, linear residue or ADEV
Each measurement row line update can optionally be output via USB or recorded on an inserted SD card
Video playlist
A video playlist with tinyGTC videos can be found here
What is the difference with a tinyPFA
The tinyPFA has no accurate internal reference and it can only measure small phase or frequency differences between two input clocks at almost equal frequencies where the tinyGTC is a universal timer/counter with an internal GPSDO as reference. The tinyPFA can measure two 10 MHz clocks with higher accuracy but it can not measure the time difference between a 1 PPS and the next up edge of a 10 MHz reference clock. The tinyGTC can measure the phase of any input clock against either the internal reference or an external 10 MHz reference
Where to buy
Zeenko store on AliExpress . This is the factory store
Eleshop in Europe
Astroradio in Spain
Mirfield Electronics in the UK.
R&L Electronics in the USA.
First use
Understanding the tinyGTC
UI
Internals
Firmware Update
Specification
Measuring PPS from a GPS module
Performance
Analyzing a input signal
TimeLab
SCPI
pyvisa
Python
GPS