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A GPS disciplined oscillator unit with a GPS antenna input, 10 MHz and 1 pulse-per-second (PPS) outputs, and an RS-232 interface.. A GPS clock, or GPS disciplined oscillator (GPSDO), is a combination of a GPS receiver and a high-quality, stable oscillator such as a quartz or rubidium oscillator whose output is controlled to agree with the signals broadcast by GPS or other GNSS satellites.
GPS encodes this information into the navigation message and modulates it onto both the C/A and P(Y) ranging codes at 50 bit/s. The navigation message format described in this section is called LNAV data (for legacy navigation). The navigation message conveys information of three types: The GPS date and time, and the satellite's status.
An oscillator whose output frequency is continuously steered (often through the use of a phase locked loop) to agree with an external reference. For example, a GPS disciplined oscillator (GPSDO) usually consists of a quartz or rubidium oscillator whose output frequency is continuously steered to agree with signals broadcast by the GPS satellites.
PPS signals are used for precise timekeeping and time measurement. One increasingly common use is in computer timekeeping, including NTP.Because GPS is considered a stratum-0 source, a common use for the PPS signal is to connect it to a PC using a low-latency, low-jitter wire connection and allow a program to synchronize to it.
The U.S. Department of Defense is required by law to "maintain a Standard Positioning Service (as defined in the federal radio navigation plan and the standard positioning service signal specification) that will be available on a continuous, worldwide basis" and "develop measures to prevent hostile use of GPS and its augmentations without ...
a frequency translator (normally composed of an oscillator and a frequency mixer) used to convert the frequency of the received signal to the frequency required for the transmitted signal, an output band-pass filter, a power amplifier (this can be a traveling-wave tube or a solid-state amplifier).
MEMS oscillator suppliers solve the diversity problem by leveraging circuit technology. While quartz oscillators are usually built with the quartz crystals driven at the desired output frequencies, [ citation needed ] MEMS oscillators commonly drive the resonators at one frequency and multiply this to the designed output frequency.
A radio transmitter design has to meet certain requirements. These include the frequency of operation, the type of modulation, the stability and purity of the resulting signal, the efficiency of power use, and the power level required to meet the system design objectives. [1]