Not being able to control the amplitude of the AD9850/51 DDS chip output waveform makes it difficult to generate decent signalling waveforms. However, this is possible by changing the current into th
I have just seen a tiny GPS module made by Trimble for embedded applications. The Lassen SK11 GPS module. It has the 1 PPS output needed for our simple frequency standards and timing purposes. The pr
It is possible to get 9dB more power out of the AD9850 and AD9851 DDS chips by using a 2+2:1 centre tapped transformer from both Iout pins with the centre tap to ground to complete a DC path. The out
Nothing over the weekend at all. Andy G4JNT "The Information contained in this E-Mail and any subsequent correspondence" "is private and is intended solely for the intended recipient(s)." "For those
Have a look at Power Basic, produced by Spectra Publishing. When Borland decided not to continue with Turbo Basic in th eearly 1090s, this organisation took it over and developed PB into a very good
Took a few seconds of the signal from Droitwich with speech modulation, downconverted to 0 - 6kHz and saved as a .WAV file. I already had some software that analyses a .WAV file for maximum and minim
Correction :-( I looked at the Droitwich carrier again after reading Jim's posting. Using the same setup as described there definitely is a dB or two of variation - had Gram on 90dB dynamic range yes
I've just made a check of both Droitwich and Donebach transmissions using the WatKins Johnson WJ-8711 receiver here at work. Using the narrowest IF bandwidth of 56Hz, setting manual gain control, and
The centre frequency would be based on that programmed in from the last update in conventional command mode - and could be that stored in EEPROM. It would be nice to calculate the increment from the
The command format for my DDS board sends the ASCII Hex characters for accumulator N value, and so the values to be sent depend on the DDS clock frequency which can have any arbitrary value. A high l
Is anyone interested in adding JASON support to my DDS board controller ? Probably by issuing a "J" command which puts the PIC controller into a loop looking for 9600 baud words on its serial port, t
I built a custom LF receiver last year, filtering to 180Hz bandwidth, then converting the signal to a 1kHz tone which was sampled by a microchip MCP3204 12 bit A/D.at 4kHz. Presumably, being made by
I have been asked by RSGB to write a paper for a forthcoming conference "Getting the Most Out of the Radio Spectrum" sponsored by the Institute of Electrical Engineers (IEE), to be held 24-25 October
OK, another test tonight and I may even forget to turn it off at bedtime ! Last night's transmission text was ' G4JNT TEST IO90IV58EI' (the last bit being my locator to a few metres accuracy) Still n
I'll carry on with the Jason test transmissions tonight. Generally the Tx is turned on when I get home, around 1600z and turned off at 2230z - so may as well continue with that. Having seen Alan's sc
OK, so frequency shift is always logically positive, incrementing modulo 17. I'll get round to writing some PIC code to make a beacn transmission with the AD9851 chip some day. There is not much poin
Must have missed something, but in looking at the coding scheme for the frequency shifts in Jason (as a preliminary to writing some PIC code to drive a DDS chip for a beacon) I came across a snag. Th
To all who have requested a copy of this IEE paper via the LF Reflector. Please contact me directly on this account [email protected] for a copy as requested. I read the LF reflector postings on a
My Poster Presentation "Amateur Use of Novel Signalling Methods at LF" shown at the IEE conference on "Getting the Most Out of the Radio Spectrum" has now happened. The full article duly appeared in
I've rather lost track of Jason to date, currently using v0.94. I believe Alberto was intending to offer a 19200 baud serial link option in a future upgrade. Currently I have a version of my DDS cont
