The target was to develop frequency generation modules that would give the best possible preparation for the future needs for low phase noise applications. This could be HTS/VHTS DSPL based payloads where Phase Noise cancelling cannot be assumed. Also with the ADC/DAC operational frequency moving upwards, the need for low phase noise frequency generation will increase. Another application could be conversion chains when Ka-band feeder traffic is moving to higher frequencies (i.e. Q&V band).
Through the development, three different frequency modules have been designed, developed and verified through breadboard testing. These are:
- FDPLO-VCSO (L-band fixed frequency, low phase noise)
- SPLO-DRO (Ku-band, DRO based, excellent phase noise)
- FDPLO-LMX (Flexible frequency from HF to Ku-band, compact design)
The overall target was that the ACE project should prepare Kongsberg Space Electronics to adapt to changing market condition, but with the clear target to establish low phase noise frequency sources. Here also the trade-off between complexity, performance and allowable cost for the system, must be taken into account.
The developed frequency generator modules are designed to meet strict requirements on phase noise and spurious performance. At the same time the frequency sources should be very flexible in the selection of output frequency to meet the need for various frequency plans of the Payload equipment. This can be achieved by flexible setting of the individual modules or where combinations of frequency sources are used.
The FDPLO-VCSO is a fractional synthesizer utilizing a SAW resonator based VCO. The design covers frequencies from 800 MHz to 2 GHz, where the frequency can be set to a selected frequency. The design combines the flexibility of selecting an output frequency independent of the reference frequency, with the superior phase noise performance of an SAW resonator VCO.
The SPLO-DRO is a Sampling Phase locked Local Oscillator (SPLO) based on a Sampling Phase Detector (SPD) and a Voltage Controlled Dielectric Resonator Oscillator. The local oscillator is designed for fixed frequency applications and covers any frequency within 8GHz to 18GHz.
The FDPLO-LMX design is based on the MMIC LMX2615 from Texas Instrument, a Space Grade 40 MHz to 15 GHz Wideband Synthesizer. This is a FDPLO which is completely integrated on a single chip, including the VCO. The only additional circuits needed are a simple loop filter, some decoupling components and voltage conditioner.
The frequency generator modules can be used in many different architectures as frequency translation is mandatory for almost all kinds of satellite communication equipment. This could be frequency conversions at the input or output of digital processors in beamforming systems. Also with the ADC/DAC operational frequency moving upwards, there is a need for low phase noise frequency sources. Another application could be conversion chains when Ka-band feeder traffic is moving to higher frequencies (i.e. Q&V band).
The project flow is lined out below:
System Study and Modules Preliminary Design: Concluded with Baseline Design Review
Modules Detailed Design & Critical Breadboarding: Concluded with Mid Term Review
Modules Manufacturing and test: Concluded with Test Review Board / Final Review
The work is completed.
Three different frequency generator breadboard modules have been developed and tested.