IQD Advanced Clock Modules
This application note introduces IQD Frequency Product’s range of advanced clock modules which provide
electrical timing functionality for distributed network systems. These units primarily revolve around the 1PPS
(pulse per second) timing synchronisation signal produced by a GPS receiver which is derived from transmitted
timing information received from GPS satellite systems.
Summary Table of Clock Module Functions
Function
1PPS
output
1PPS
input
10MHz
output
Internal
GPS
Holdover
1.5μs over
24hrs
NMEA
Rx/Tx
SGMII
& SPI
UART/
RS232
Aerial
input
Module
IQCM-100
✓
✓
✓
-
✓
-
-
✓
-
IQCM-110
✓
-
✓
✓
✓
✓
-
-
✓
IQCM-200
✓
✓
✓
-
*
-
-
✓
-
IQCM-300
✓
✓
✓
-
✓
-
✓
✓
-
* The IQCM-200 is intended for reduced holdover spec applications.
Clock Module Summary Information
IQCM-100
This main module is designed to provide both 1PPS and 10MHz output signals with a holdover stability of ±1.5μs
over a 24hr period to meet telecom standard requirements for applications such as LTE-TDD. The IQCM-100
requires a separate customer supplied 1PPS signal from a GPS receiver.
IQCM-110
The IQCM-110 module has similar functionality to the IQCM-100 except that it has a built-in GPS receiver unit. The
customer however must provide a suitable aerial connected to the SMA connector on the device. Active antenna is
recommended.
IQCM-200
This module also has similar functionality to the IQCM-100 device but is available with relaxed holdover
specifications of increased times or smaller temperature variation limits to address applications where ±1.5μs over
24hrs is not critical.
IQCM-300
This module provides PTP (Precision Time Protocol) functionality based on IEEE1588.
PTP or IEEE1588 is a protocol used to send accurate timing synchronisation between different locations on a
network. The IQCM-300 is capable of acting as a ‘Grand Master clock’ within a system or as a ‘Slave clock’ and as
such is capable of passing synchronisation messages to other clocks in the system. This module provides the
same holdover capability as the IQCM-100 but has the added functionality that it can communicate across the PTP
1588 network. The IQCM-300 requires a separate customer supplied GPS receiver.
Typical Applications include:
3G/4G LTE Base-stations
Clock Server
Clock Source
IP Backhaul
PTP Server
Radar
Smart Power Grid
Test & Measurement