The PMM002 Phase Modulator design combines digital techniques with non-traditional analog circuitry. The shortcomings of a traditional (purely analog) Phase Modulator are minimized.

Features

• 6U VME Card
• 140 MHz Output
• 15 MHz Output
• Modulation Rate: DC to 6 MHz
• Modulation Index: 0 to pi
• Synchronizes To Station Clock

The design of the PMM002 uses a combination of Direct Digital Synthesis (DDS) and analog devices operating in their linear range to generate a Phase Modulated RF (140 MHz) signal. A Numerically Controlled Oscillator (NCO) digitally generates the first IF yielding a very accurate, repeatable and linear signal with easily adjustable parameters that include frequency and modulation index.

Linear multipliers (instead of saturated diode mixers or step recovery diodes) are used for up-conversion to RF. Using linear multipliers results in significantly reduced harmonics and IM (Inter- Modulation) terms and therefore, eases filtering requirements. The resulting RF signal is easily translated to higher frequency bands, e.g. L, S, C, X or K.