Programmed Test Sources, Inc. Logo. PTS Frequency Synthesizers...Fast Switching, Low Noise RF and LO Sources.
Synthesizer Specifications (Select Model)
PTS 040
PTS 120
PTS 160
PTS 250
PTS 310
PTS LN310
PTS 500
PTS 620
PTS 1600
PTS 3200
PTS 6400
PTS x10
PTS D310
PTS D620

PTS offers one of the most complete lines of frequency synthesizers available in the industry. Our models all use our own direct synthesis systems. Their advantages over competitive designs include excellent specifications with low phase noise, fast switching speed and low spurious outputs along with low complexity.

Each model is a direct frequency synthesizer capable of providing signals for many uses requiring stable and accurate sine-wave signals with low spurious outputs, low phase noise and fast switching between selected frequencies. Typical applications include wireless communications, precision clock sources, radar and surveillance systems and automatic test systems (ATE) with both narrow and wide-band coverage. Options based on a modular design concept permit a high degree of adaptation to a customer's specific needs.

To learn more about our product specifications and pricing, request a catalog today. If you have questions about applicability or performance detail, contact PTS; demonstrator models are available for evaluations.
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INTRODUCTION TO PTS SYNTHESIZERS

PTS frequency synthesizers are precision frequency generators. They transfer the accuracy and stability of a frequency standard operating at 5.0 or 10.0 MHz, either built-in or external, to a selectable output frequency.

Each model is a direct frequency synthesizer capable of providing signals for many uses requiring stable and accurate sine-wave signals with low spurious outputs, low phase noise and fast switching between selected frequencies. Typical applications include communications, spectrum analysis and surveillance, radar and automatic test systems (ATE) with both narrow and wide-band coverage. Options based on a modular design concept permit a high degree of adaptation to a customer’s specific needs.

Up to ten significant figures and resolution to 0.1 Hz are available; custom higher resolution is also available. All output frequencies are coherent with the standard frequency and reflect its stability and accuracy. Any frequency within the instrument’s range may be selected by manual dial or by remote control. The output from the levelled system is +3 to +13 dBm (for most models) into 50 ohms and may be adjusted manually by the front panel control or remotely by analog voltage.

PTS synthesizers offer a choice of the two most widely-used remote interfaces. Instruments may be equipped with either the BCD-parallel (buffered) or the GPIB (IEEE 488) interface. In addition, PTS now offers the industry's fastest GPIB list-processing capability; this enhanced interface features full IEEE 488.2 and SCPI capability.

The PTS systems of synthesis drastically cut complexity and parts count. The attendant reduction of primary power input and dissipation (less than 50% of that of competitive designs) is a major factor in the reliability, which is further enhanced by a packaging system maximizing mechanical integrity and stability while keeping weight low. For ease of service, most modules are of plug-in design and used in all models.

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REMOTE CONTROL INTERFACES

For remote-control or computer-controlled applications, all PTS synthesizers are equipped with either a standard parallel BCD interface, or an optional GPIB-compatible interface. (Lower cost remote-only units are available which include no manual control capability.) With both interfaces, output signal frequency, output signal level, and remote/local mode control are programmable.

Parallel BCD Interface

The parallel BCD interface employs a 50-pin Amphenol 57-40500-compatible connector on the equipment, and requires an Amphenol 57-30500-compatible connector for control.

In the standard parallel BCD interface, output signal frequency programming and remote/local mode control programming use TTL-level negative true logic. Output signal level programming uses a DC control voltage.

The programming format for frequency control is parallel, 4 bit BCD coding for each digit (decade). All frequency programming connects to, and can be driven by, industry standard 74HCT-type ICs. By default, all frequency control lines are internally pulled to a high (false) state; to program a specific frequency the appropriate pins must be brought to the low (true) state.

Data latches are included which provide storage when a "latched" or "buffered" mode of operation is required. By default, all Latch Enable (LE) pins are internally pulled to a high (false) state, disabling the latches. To store remote frequency programming input, the LE pins are brought to the low state. To operate in a "transparent" (i.e., non-latched) mode, the LE pins may be left unconnected. A separate LE line is provided for each digit pair (8 bits) so that operation with serial frequency programming data bytes is possible.

The output signal level is programmed via a DC control voltage. The RMS RF output voltage is one-half (0.5) the DC analog voltage present on the output-level control pin (0.63 to 2.0 VDC, corresponding to 0.315 to 1.0 Vrms output into 50 ohms).

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GPIB Interface

The GPIB interface employs an IEEE-488 24-pin female connector on the equipment, and requires an IEEE-488 24-pin male connector for control.

PTS offers two versions of the GPIB interface:

-a fast-switching legacy version which is IEEE 488.1(1987)-compliant. It allows the synthesizer to act as a basic listener device (no talk capabilities), and provides control of the two device-dependent functions output signal frequency and level. Output signal frequency can be programmed in 30 µseconds or less to the instrument’s full resolution; signal level is programmed from + 4 dBm to +13 dBm in 1 dB steps.

-a fully IEEE 488.2/SCPI-compliant interface. It allows complete control over all instrument functions and status. Switching speeds are 5 - 10 mseconds, or less than 250 µseconds in the LIST mode of operation.

The PTS GPIB can be controlled via special-purpose GPIB controllers. Alternatively, a number of manufacturers provide low-cost board-level products for microcomputers which implement the IEEE-488 interface. The PTS GPIB remote-control interface is compatible with such products.

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FREQUENCY SWITCHING BEHAVIOR

In all PTS synthesizers, the most significant digits down to 1 MHz (all produced by direct analog technology) have phase-coherent frequency switching.

For applications requiring high-speed, phase-continuous frequency switching, PTS offers the Direct Digital Synthesis Table Look Up (DDS-TLU or DDS) option. With this option, the standard direct analog low-resolution subsection of an instrument is replaced with a direct digital subsection capable of generating the required low-resolution frequency increments. The DDS can provide phase-continuous frequency switching, and less than 1 µs switching time (with 2 µs delay). The following versions are available:
  • Version H – DDS option replaces the 100 KHz through 0.1 Hz subsection. Phase continuity can be maintained during frequency switches involving the 100 KHz through 0.1 Hz digits. Spurious outputs are -60 to -70 dBc.
  • Version K – DDS option replaces the 10 KHz through 0.1 Hz subsection. Phase continuity can be maintained during frequency switches involving the 10 KHz through 0.1 Hz digits. Spurious outputs are -65 to -75 dBc.
The DDS option is available for PTS models 040, 120, 160, 250, 500 and 620. (DDS high speed, phase-continuous switching is standard in the PTS model 310, 1600, 3200, 6400, x10, D310 and D620.) Note that the spurious specifications for the versions differ, reflecting the tradeoff between bandwidth coverage and spurious output; consult instrument specifications for details.

In instruments using the analog mix-and-divide technology for steps from 100 KHz down to 0.1 Hz, frequency switches have limited, though arbitrary, phase discontinuities. In principle, a frequency switch using the 100 KHz digit may have at most a 180° phase jump, a frequency switch using the 10 KHz digit at most an 18° phase jump, 1 KHz at most 1.8°, 100 Hz at most 0.18°, 10 Hz at most .018°, 1 Hz at most .0018°, 0.1 Hz at most .00018°. For all practical purposes, frequency switches of 100 Hz or less may be considered phase-continuous in these instruments.

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FREQUENCY STANDARDS

The output frequency of a PTS synthesizer reflects directly the accuracy of the controlling frequency standard, either internal or external. PTS offers a choice of two internal standards: a high-stability oven-controlled crystal oscillator (OCXO), or a moderate-stability temperature-compensated crystal oscillator (TCXO).

All quartz crystal oscillators are secondary standards which require a primary reference for calibration. PTS oscillators are set to within 1x10-7 of nominal at the time of delivery from the factory. Thereafter, these oscillators are subject to the time-drift and temperature-drift given in the specifications. Both PTS oscillators include field-adjustment capability for up to five years of aging.

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