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1PPS In/Out, 10 MHz In [1204-01, -03]

Model 1204-01, 1PPS/Freq Input (TTL): General Specifications

  • Inputs/Outputs: One Frequency Input (=J1), one 1PPS Input (=J2), one 1PPS Output
  • Signal Type And Connector: TTL/Sine (BNC into 50 Ω)
  • Maximum Number of Cards: 6
  • Ordering Information: 1204-01: 1PPS/Freq input (TTL levels) module

Model 1204-01 option card rear plate

Model 1204-03, 1PPS/Freq Input (RS-485): General Specifications

  • Inputs/Outputs: (1) 1PPS Input, (1) Freq Input (1) 1PPS Output. All input and output signals are RS-485 compatible.
  • Signal Type And Connector: Balanced RS-485 (3.8 mm terminal block)

  • Maximum Number of Cards: 6
  • Ordering Information: 1204-03: 1PPS/Freq input (RS-485 levels) module

Model 1204-03 option card rear plate

Model 1204-03 1PPS/Freq Input: Connector pin assignment

Pin No. Signal Function
1 GND Ground
2 FREQIN_RS485+ RS-485 Frequency Input +
3 FREQIN_RS485- RS-485 Frequency Input –
4 GND Ground
5 PPSIN_RS485+ RS-485 1PPS Input +
6 PPSIN_RS485- RS-485 1PPS Input –
7 GND Ground
8 PPSOUT_RS485+ RS-485 1PPS Output +
9 PPSOUT_RS485- RS-485 1PPS Output –
10 GND Ground

Models 1204-01,-03: Input/Output Specifications

FREQ Input Specifications

  • Signal Type And Connector: Sine wave (BNC)
  • Detected Level: +13 dBm to -6dBm
  • Frequency Setting: 1KHz…10 MHz in 1Hz steps

1PPS Input Specifications

  • Input Impedance: 50 Ω
  • Minimum Pulse Width detected: 100 ns
  • Input Signal Jitter: <±500 ns t o achieve oscillator lock, <±50 ns to achieve system performance
  • Programmable Phase Shift: ±5ns to 500 ms with 5ns resolution

1PPS Output Specifications

  • Signal Type And Connector: TTL level (BNC)
  • Output Load Impedance: 50 Ω
  • Rise Time to 90% of Level: <10 ns
  • Programmable Pulse Width: 100 ns to 900 ms with 20 ns resolution
  • Absolute Phase Error: ±50 ns (1σ)
  • Programmable Phase Shift: ±5ns to 500 ms with 5ns resolution

1PPS Input and Output: Viewing Signal State

To quickly view if the PPS inputs and outputs of this option card are currently enabled or disabled, go to the option card’s Status Summary panel. For instructions, see: Viewing an Input/Output Signal State.

1PPS Input: Edit Window

To configure the settings for the 1PPS Input (also referred to as ‘Reference’), go to its Edit window. For instructions, see: Configuring Option Card Inputs/Outputs.

The Web UI list entries for these cards are: 1PPS/Frequency BNC and 1PPS/Frequency RS-485. The connector number is: J2 (Model 1204-03: RS-485 connector: Pins 5 and 6)

Note: SecureSync starts numbering I/O ports with 0 (only 1PPS and 10 MHz outputs start at 1, because of the built-in outputs).

The Edit window allows the configuration of the following settings:

  • Edge: The operator can select either the rising or the falling edge as the input time reference (defines the on-time point of the signal).
  • Offset: It is possible to add an offset to the input signal (to account for cable delays), with a resolution of 5ns and a positive or negative value of 500 ms maximum.

1PPS Input: Status Window

To view the current settings of the PPS Input (also referred to as ‘Reference’), go to its Status window. For instructions, see: Verifying the Validity of an Input Signal.

The Web UI list entries for these cards are: 1PPS/Frequency BNC and 1PPS/Frequency RS-485. The connector number is: J2 (Model 1204-03: RS-485 connector: Pins 5 and 6)

Note: SecureSync starts numbering I/O ports with 0 (only 1PPS and 10 MHz outputs start at 1, because of the built-in outputs).

The Status window displays the following settings:

  • Reference ID: Name used to represent this 1PPS input reference in the Reference Priority table; see Configuring Input Reference Priorities for more information on reference priority configuration.
  • 1PPS Validity: Indicates “OK” (green) if the 1PPS input signal is present and valid. Indicates “Not Valid” (orange) if the 1PPS input signal is either not present or is not considered valid.
  • Edge: Displays the selected Edge (rising of falling) of the 1PPS input that defines the on-time point.
  • Offset: Displays the configured 1PPS offset values.

The 1PPS Input signal is analyzed and an absence of the signal triggers a “Not Valid” indication.

Frequency Input: Edit Window

To configure the settings for the Frequency Input (also referred to as ‘Reference’), go to its Edit window. For instructions, see: Configuring Option Card Inputs/Outputs.

The Web UI list entries for these cards are: 1PPS/Frequency BNC and 1PPS/Frequency RS-485. The connector number is: J1 (BNC card); J1 (RS-485 card).

Note: SecureSync starts numbering I/O ports with 0 (only 1PPS and 10 MHz outputs start at 1, because of the built-in outputs).

The Edit window allows the configuration of the following settings:

  • Reference Mode: Used to control how the reference mode operates in determining its validity. Values are:
    • Primary Reference—Allows the frequency reference to be valid based solely on its own presence.
    • Secondary Reference—Requires another valid reference to synchronize the system before the frequency reference can be determined to be valid. This is used when the frequency reference is intended to operate as a backup reference to a different primary reference source.
  • Frequency: Used to configure the frequency (in Hertz) of the input signal. The available Frequency range is 1KHz…10 MHz in 1Hz steps.

The input frequency is measured versus internal frequency and compared to the setup value. If the discrepancy is larger than 1kHz, the input is disqualified and not considered valid. The frequency reference does not inherently provide an on-time point, so it relies on the current on-time point of the system prior to its taking over for synchronization.

Frequency Input: Status Window

To view the current settings of the Frequency Input (also referred to as ‘Reference’), go to its Status window. For instructions, see: Viewing Input/Output Configuration Settings.

The Web UI list entries for these cards are: 1PPS/Frequency BNC and 1PPS/Frequency RS-485.

The connector number is: J1 (BNC card); J1 (RS-485 card).

Note: SecureSync starts numbering I/O ports with 0 (only 1PPS and 10 MHz outputs start at 1, because of the built-in outputs).

The Status window displays the following settings:

  • Reference ID: Name used to represent this 1PPS input reference in the Reference Priority table; see Configuring Input Reference Priorities for more information on reference priorities.
  • 1PPS Validity: Indicates “OK” (green) if the 1PPS input signal is present and valid. Indicates “Not Valid” (orange) if the 1PPS input signal is either not present or is not considered valid.
  • Reference Mode: Displays how the reference mode operates in determining its validity.
  • Frequency: Displays (in Hertz) the configured frequency of the input frequency signal.

The 1PPS Input signal is analyzed and an absence of the signal triggers a “Not Valid” indication.

1PPS Output: Edit Window

To configure the settings of the 1PPS output, go to its Edit window. For instructions, see: Configuring Option Card Inputs/Outputs.

The Web UI list entries for these cards are: 1PPS/Frequency BNC and 1PPS/Frequency RS-485.

The connector number is: J3 (BNC card); J1 (RS-485 card).

Note: SecureSync starts numbering I/O ports with 0 (only 1PPS and 10 MHz outputs start at 1, because of the built-in outputs).

The Edit window allows the configuration of the following settings:

  • Signature Control: Used to control when the 1PPS output signal will be present. See Signature Control for more information.
  • Offset: Used to account for 1PPS cable delays or other latencies in the 1PPS output. The Offset value is entered and displayed in nanoseconds (ns). The available Offset range is -500 to +500 ms.
  • Edge: The operator can select if the output signal is a positive (reference on the rising edge) or a negative (reference on the falling edge) pulse.
  • Pulse Width: Configures the Pulse Width of the 1PPS output. The Pulse Width is entered and displayed in nanoseconds (ns). The default Pulse Width is 200 milliseconds.

PPS Output: Status Window

To view the current settings of the 1PPS output, go to its Status window. For instructions, see: Viewing Input/Output Configuration Settings.

The Web UI list entries for these cards are: 1PPS/Frequency BNC and 1PPS/Frequency RS-485.

The connector number is: J3 (BNC card); J1 (RS-485 card).

Note: SecureSync starts numbering I/O ports with 0 (only 1PPS and 10 MHz outputs start at 1, because of the built-in outputs).

The Status window displays the following settings:

  • Signature Control: Displays the current configuration of Signature Control. See also: Signature Control.
  • Frequency: Indicates the configured frequency of the 1PPS output signal.
  • Offset: Displays the configured Offset (to account for cable delays or other latencies).
  • Edge: Shows if the on-time point of the 1PPS output is the rising or falling edge of the pulse.
  • Pulse Width: Displays the configured Pulse Width of the 1PPS output. The Pulse Width is displayed in nanoseconds (ns). The default Pulse Width is 200 milliseconds.