z-wave RF PHY conformance tests for z-wave device testing
RF and PHY conformance tests for z-wave device testing is covered here. These compliance tests are used for transmitter and receiver measurements of z-wave device.
Refer article on physical layer measurements and tutorial on RF measurements in order to understand basics of both.
Z-wave device transmitter conformance testing
Z-wave conformance tests for the transmitter part include transmit frequency error, RF data rate, modulation-code rate, transmit RF power, power adjustments etc. These transmitter tests are useful for z-wave device testing.
Transmit Frequency Error: It is defined as difference between measured transmitted centre frequency and
ideal center frequency. The frequency error should not exceed +/-27ppm.
This includes crystal ageing over the 5 year period.
RF Data rate: z-wave PHY layer should support following data rates
with accuracy of +/-27ppm.
| Rate | Bit rate | Symbol rate |
|---|---|---|
| R1 | 9.6 Kbps | 19.2 Kbaud |
| R2 | 40 Kbps | 40 Kbaud |
| R3 | 100 Kbps | 100 Kbaud |
Modulation Code rate: It supports (FSK,manchester) for R1 rate, (FSK,NRZ) for R2 rate,
(GFSK,NRZ) for R3 rate. Allowed separation is 40 kHz+/-10% for R1 and R2 rates.
Allowed separation is 58KHz +/- 10 % for R3 rate.
Transmit RF power: It is measured at the antenna connector.
It should meet local regulatory requirements.
Power Adjustments: It should able to reduce at least
nominal output power-20 dB.
Z-wave device receiver conformance testing
Z-wave conformance tests for the receiver part include receiver sensitivity, clear channel assessment, receiver spurious measurements, receiver blocking test, maximum input level, Tx-Rx turnaround time, Rx-Tx turnaround time etc. These receiver tests are useful for z-wave device testing.
Receiver sensitivity: The test is conducted as per standard test frame and conditions mentioned
in the standard. The receiver sensitivity for different rates should meet following requirements:
| Bit Rate | Minimum Receiver sensitivity |
|---|---|
| R1 | -95dBm |
| R2 | -92dBm |
| R3 | -89dBm |
Clear Channel Assessment: The z-wave physical layer need to perform this test in order to determine if the medium is busy or clear for the transmission. The receiver should be able to perform 'listen before talk' with threshold of about -80dBm.
Receiver spurious measurement: The RX spurious limit is -70 dBm at 100 kHz within +/- 1 MHz from the regional Z-Wave frequency.
Z-wave receiver blocking test
Receiver Blocking test: Blocking is a measure of the capability of the receiver to receive a wanted modulated signal without exceeding a given degradation due to the presence of an unwanted input signal.
• Standard test frame is at the nominal frequency with normal modulation.
Its power is adjusted down to the sensitivity level +3 dB.
• Unwanted signal is a CW (carrier wave) at a specific offset frequency. Its power is adjusted
up until the receiver gets the FER (frame error rate) that correspond to the sensitivity level.
| Frequency offset | Receiver blocking limit |
|---|---|
| +/-1 MHz | -44dBm |
| +/-2 MHz | -34dBm |
| +/-5 MHz | -27dBm |
| +/-10 MHz | -25dBm |
Maximum input level:
A receiver shall function with maximum input level greater than or equal to 0 dBm
(i.e. 1mW).
Tx-Rx turnaround time: It is measured from the trailing edge of the last transmitted
symbol until the receiver is ready to begin the reception of the next PHY packet.
The limit specified in the standard is about 1 ms.
Rx-Tx turnaround time: It is measured at the receiver from the trailing edge of the last
symbol of a received packet until the transmitter is ready to begin transmission.
The limit specified in the standard is about 1 ms.
Similar posts on z-wave technology
z-wave tutorial
z-wave physical layer-PHY
z-wave MAC layer
z-wave protocol stack
z-wave security basics
z-wave device conformance testing