woodpecker
Member
- Joined
- Aug 7, 2005
- Messages
- 729
As we all know the frequency error and drift on the DV10 is caused by a serious hardware design fault. Rather than address the issue properly and fix the hardware AOR have tried a firmware botch (which doesn't work well), we have been analysing exactly what AOR have done in the firmware.
In firmware they take the raw hex temperature value from the sensor in the RX63 cpu and calculate the CPU temperature in 0.1 degree C steps. They then use this temperature in 2 calculations to step the PLL_REF and frequency OFFSET around to "TRY" and keep it on frequency. If you listen to a 1kHz AM modulated signal in SSB you can hear (and see using an audio spectrum analyser) the 1kHz signal jumping around and warbling away as the 2 adjustments jump around.
The equations used to jump the PLL_REF and OFFSET around are identical but use different sets of constants, the equations are as below where C1 to C4 are the 4 constants:-
Offset = (CPU Temp - C1) x ((C4 - C3) / (C2 - C1)) + C3
The calculations operate across the cpu temperature range -15.1 to +79.9, at the upper and lower limits the constants for the calculations change in 10 degree blocks and in 5 degree blocks arcross the mid range.
Not only have they turned the DV10 into something that warbles its XCO like an MFSK signal, they also managed to get the temperature gradients wrong, the DV10 still drifts, is still of frequency but now warbles like a dying bird.
I would seem AOR have lost the plot with regards to receiver design, this is an absoluted botched mess.
In firmware they take the raw hex temperature value from the sensor in the RX63 cpu and calculate the CPU temperature in 0.1 degree C steps. They then use this temperature in 2 calculations to step the PLL_REF and frequency OFFSET around to "TRY" and keep it on frequency. If you listen to a 1kHz AM modulated signal in SSB you can hear (and see using an audio spectrum analyser) the 1kHz signal jumping around and warbling away as the 2 adjustments jump around.
The equations used to jump the PLL_REF and OFFSET around are identical but use different sets of constants, the equations are as below where C1 to C4 are the 4 constants:-
Offset = (CPU Temp - C1) x ((C4 - C3) / (C2 - C1)) + C3
The calculations operate across the cpu temperature range -15.1 to +79.9, at the upper and lower limits the constants for the calculations change in 10 degree blocks and in 5 degree blocks arcross the mid range.
Not only have they turned the DV10 into something that warbles its XCO like an MFSK signal, they also managed to get the temperature gradients wrong, the DV10 still drifts, is still of frequency but now warbles like a dying bird.
I would seem AOR have lost the plot with regards to receiver design, this is an absoluted botched mess.