The TADD-2 Mini (or "T2-Mini") is a tiny frequency divider board
that accepts a 1, 2.5, 5 or 10 MHz input signal and generates a 1
pulse-per-second ("PPS") output pulse. The pulse can be synchronized to
an external source (such as a GPS receiver). The divider is implemented
in a DIP-socketed PIC chip using software written by Tom Van Baak. The
source code is freely available, and other
software loads are available from Tom's web site to implement different
division ratios.
Tests indicate that the jitter is in the range of 1 picosecond -- near the noise floor of the best test systems we've been able to configure. The input circuit is a wide-range design that works with signals from -20 to +13 dBm. The input may be high impedance, or terminated in 50 ohms via a jumper.
The T2-Mini has a single low-impedance output that delivers greater than 3.5 volts into a 50 ohm load, with rise time at the connector of less than 3 nanoseconds. In addition to the primary output, optional headers on the board provide either an LED or an auxiliary TTL-level output signal, and an inverted TTL-level pulse.
Power input is from 9 to 15 volts and current draw is from 20 to 50 milliamps, depending on output load.
An 8-pin header provides direct access to four of the PIC's pins; these may be used for configuration or additional input signals. The pre-programmed PIC that TAPR provides uses the 8 pin header to allow selection of four input frequencies -- 1, 2.5, 5, or 10 MHz -- and synchronization of the divider to an external clock source.
The board is only 0.75 by 2.0 inches and uses surface mount parts, although the PIC chip is a socketed 8 pin DIP to allow easy reprogramming.
Availability
The T2-Mini is available for ordering now. Shipment to start on about April 18, 2011.Because of the small size and tightly packed surface mount components, the TADD-2 Mini is available only with all SMT parts installed. TAPR is offering three options:
- The PCB with all SMT parts installed, but no other parts included (this means you will have to provide your own PIC chip as well as socket, connectors and headers). (T2- Mini Basic)
- A semi-kit that includes the PCB with all SMT parts installed, plus connectors, headers, socket, and programmed PIC chip to be installed by the user. When completed it will be as shown in the images above. (T2-Mini w/connectors)
- A fully assembled unit. (T2-Mini - Assembled)
The T2-Mini Basic requires you to provide and program your own PIC chip.
Ordering Information
The price for the T-2 Mini Basic is:
$ 39 US for members of TAPR
$ 44 US for non-members
+ shipping/handling if applicable.
(Place Web Order)
Shipping and Handling
Shipping and Handling within the US will be by USPS Priority Mail.New International Shoppers will be contacted by the TAPR office with a quote on the shipping costs to your country. Returning customers are expected to be aware of international costs, ask if unsure. TAPR uses insured Priority Mail International, unless the purchaser requires something else.
The T2-Mini w/connectors includes PIC and other through hole parts which you must assemble to the board which already has the SMT parts installed.
Ordering Information
The price for the T-2 Mini w/connectors is:
$ 49 US for members of TAPR
$ 55 US for non-members
+ shipping/handling if applicable.
(Place Web Order)
Shipping and Handling
Shipping and Handling within the US will be by USPS Priority Mail.New International Shoppers will be contacted by the TAPR office with a quote on the shipping costs to your country. Returning customers are expected to be aware of international costs, ask if unsure. TAPR uses insured Priority Mail International, unless the purchaser requires something else.
Price of the T2-Mini - Assembled unit is still to be determined.
Price is TBD
Assembly and Operations Manual
The assembly and operations manual can be found online at http://www.tapr.org/~n8ur/T2_Mini_Manual.pdf.
Software
Code as programmed in the PIC supplied in the T2-Mini kit w/connectors.
Other variations written by Tom Van Baak here.
Support
TAPR kits can be complex depending on the kitting experience of each builder. We don't think you will have trouble with the kit, but it does require some knowledge and experience to successfully go from a kit to a finished, usable unit, depending on the mode of operations.
Questions concerning the construction and operation of the TADD-2 Mini kit are discussed on the time-freq mailing list. To subscribe, click here.
Acknowledgments
The TAPR TADD-2 Mini was made possible by the efforts of:
John Ackermann, N8UR – Designer and Project Manager
Tom Van Baak – Software AuthorBeta Testers:
Tom Van Baak
John Miles, KE5FX
