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Member | Action | Date |
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Robert Anderson |
Updated
to
AFSK signal demodulation with EZRadioPro
Part II of my reply...
Thanks for the clarification. I did have NDCE2 set as disabled for the 4463 (C2A) boards running in 4464 compatibility mode. Good to know that was already correct.
Thank you for the information on how to get the result required from WDS. I have to figure out a scheme to reset/restart the gear switch in AFSK mode (perhaps mission impossible due to the PWM front end and the decoder back end operating primarily asynchronously). However, It should be possible for 2FSK so I will definitely produce some coefficients and give gear switching a try for 2FSK RX when I get to that stage.
I found a formula in the API docs and an EZR Reference Manual(s) for expressing RSSI in dBM. This was dBm = ((RSSI / 2) - Si446x_MODEM_RSSI_COMP_VALUE - 70). Another formula in the EZR document gives RSSIdBm = (RSSI_value/2) - 130 which fails to consider the MODEM_RSSI_COMP. For this next formula with the default for MODEM_RSSI_COMP of 64 the offset value is 70 + 64 = 134 which is different to the 130 in the first formula. Anyway could you confirm the above first formula I have used is correct or advise a correction if it is wrong?
I have code that calculates and sets the IF_FREQ as required using the formulas in the API docs. However, there is no formula for calculating FREQ_CONTROL_VCOCNT_RX_ADJ in the API docs. I deduced this calculation to be = -((FREQ_IF * OUTDIV) / (PRESCALER * WSIZE)) / XO and am currently using that. Is my deduced formula correct?
Can you provide a formula for calculating the AFC limiter?
Thanks and best regards
Robert |
Jan 12 2019, 1:57 PM |

Robert Anderson |
Updated
to
AFSK signal demodulation with EZRadioPro
Part II of my reply...
Thanks for the clarification. I did have NDCE2 set as disabled for the 4463 (C2A) boards running in 4464 compatibility mode. Good to know that was already correct.
Thank you for the information on how to get the result required from WDS. I have to figure out a scheme to reset/restart the gear switch in AFSK mode (perhaps mission impossible due to the PWM front end and the decoder back end operating primarily asynchronously). However, It should be possible for 2FSK so I will definitely produce some coefficients and give gear switching a try for 2FSK RX when I get to that stage.
I found a formula in the API docs and an EZR Reference Manual(s) for expressing RSSI in dBM. This was dBm = ((RSSI / 2) - Si446x_MODEM_RSSI_COMP_VALUE - 70). Another formula in the EZR document gives RSSIdBm = (RSSI_value/2) - 130 which fails to consider the MODEM_RSSI_COMP. For this next formula with the default for MODEM_RSSI_COMP of 64 the offset value is 70 + 64 = 134 which is different to the 130 in the first formula. Anyway could you confirm the above first formula I have used is correct or advise a correction if it is wrong?
I have code that calculates and sets the IF_FREQ as required using the formulas in the API docs. However, there is no formula for calculating FREQ_CONTROL_VCOCNT_RX_ADJ in the API docs. I deduced this calculation to be = -((FREQ_IF * OUTDIV) / (PRESCALER * WSIZE)) / XO and am currently using that. Is my deduced formula correct?
Can you provide a formula for calculating the AFC limiter? Thanks and best regards
Robert |
Jan 12 2019, 1:55 PM |

Robert Anderson |
Updated
to
AFSK signal demodulation with EZRadioPro
Part II of my reply...
Thanks for the clarification. I did have NDCE2 set as disabled for the 4463 (C2A) boards running in 4464 compatibility mode. Good to know that was already correct.
Thank you for the information on how to get the result required from WDS. I have to figure out a scheme to reset/restart the gear switch in AFSK mode (perhaps mission impossible due to the PWM front end and the decoder back end operating primarily asynchronously). However, It should be possible for 2FSK so I will definitely produce some coefficients and give gear switching a try for 2FSK RX when I get to that stage.
I found a formula in the API docs and an EZR Reference Manual(s) for expressing RSSI in dBM. This was dBm = ((RSSI / 2) - Si446x_MODEM_RSSI_COMP_VALUE - 70). Another formula in the EZR document gives RSSIdBm = (RSSI_value/2) - 130 which fails to consider the MODEM_RSSI_COMP. For this next formula with the default for MODEM_RSSI_COMP of 64 the offset value is 70 + 64 = 134 which is different to the 130 in the first formula. Anyway could you confirm the above first formula I have used is correct or advise a correction if it is wrong?
I have code that calculates and sets the IF_FREQ as required using the formulas in the API docs. However, there is no formula for calculating FREQ_CONTROL_VCOCNT_RX_ADJ in the API docs. I deduced this calculation to be = -((FREQ_IF * OUTDIV) / (PRESCALER * WSIZE)) / XO and am currently using that. Is my deduced formula correct?
Thanks and best regards
Robert |
Jan 12 2019, 4:10 AM |

Robert Anderson |
Updated
to
AFSK signal demodulation with EZRadioPro
Part II of my reply...
Good to know that was already correct.
Thank you for the information on how to get the result required from WDS. I have to figure out a scheme to restart the gear switch in AFSK mode (perhaps mission impossible due to the PWM front end and the decoder back end operating primarily asynchronously).
I found a formula in the API docs and an EZR Reference Manual(s) for expressing RSSI in dBM. This was dBm = ((RSSI / 2) - Si446x_MODEM_RSSI_COMP_VALUE - 70).
I have code that calculates and sets the IF_FREQ as required using the formulas in the API docs. However, there is no formula for calculating FREQ_CONTROL_VCOCNT_RX_ADJ in the API docs. Is my deduced formula correct?
Thanks and best regards
Robert |
Jan 10 2019, 3:28 AM |

Robert Anderson |
Updated
to
AFSK signal demodulation with EZRadioPro
Part II of my reply...
Good to know that was already correct.
Thank you for the information on how to get the result required from WDS. I have to figure out a scheme to restart the gear switch in AFSK mode (perhaps mission impossible due to the PWM front end and the decoder back end operating primarily asynchronously).
I found a formula in the API docs and an EZR Reference Manual(s) for expressing RSSI in dBM. This was dBm = ((RSSI / 2) - Si446x_MODEM_RSSI_COMP_VALUE - 70). For this next formula the default for MODEM_RSSI_COMP is 64 so 70 + 64 = 134 which is different to the 130 in the first formula.
I have code that calculates and sets the IF_FREQ as required using the formulas in the API docs. However, there is no formula for calculating FREQ_CONTROL_VCOCNT_RX_ADJ in the API docs. Is my deduced formula correct?
Thanks and best regards
Robert |
Jan 10 2019, 3:24 AM |

Robert Anderson |
Updated
to
AFSK signal demodulation with EZRadioPro
Part II of my reply...
Good to know that was already correct.
Thank you for the information on how to get the result required from WDS. I have to figure out a scheme to restart the gear switch in AFSK mode (perhaps mission impossible due to the PWM front end and the decoder back end operating primarily asynchronously).
I found a formula in the API docs and an EZR Reference Manual(s) for expressing RSSI in dBM. This was dBm = ((RSSI / 2) - Si446x_MODEM_RSSI_COMP_VALUE - 70). For this next formula the default for MODEM_RSSI_COMP is 64 so 70 + 64 = 134 which is different to the 130 in the first formula.
I have code that calculates and sets the IF_FREQ as required using the formulas in the API docs. However, there is no formula for calculating FREQ_CONTROL_VCOCNT_RX_ADJ in the API docs. Is my deduced formula correct?
Thanks and best regards
Robert |
Jan 10 2019, 3:24 AM |

Robert Anderson |
Updated
to
AFSK signal demodulation with EZRadioPro
Hi Zoltan, Apologies for slow reply. I didn't have follow set on this post so didn't get a notification. Fixed now. Part I of my reply...
A: The configuration which performed the best was using the 4464 (B1B) with output of RAW_RX_DATA which is then processed by a DSP chain in the MCU (STM32). Using RX_DATA and LCM (26.4ksps) method did not perform as well. Also 4463 (C2A) running as 4464 compatible does not perform as well as 4464. The data rate in WDS I set for the RAW_RX operation is a simple 1.2ksps. Subsequent to those tests there have been many changes to the front end PWM handler, HDLC handler and DSP filter/decode processing code. The decode success rate has been improved substantially in general and also under conditions of heavy RX traffic . e.g. During high altitude balloon flights (one use case for this project) the AFSK traffic is often continuous/overlapping. Anyway I will try the LCM (26.4ksps) method driving RX_DATA again shortly and see if there remains a verifiable difference between the 1.2ksps outputting RAW_RX and the 26.4ksps output BCR managed RX_DATA. The majority of the 446x driver code is now able to support changes of band and PHY, etc. for AFSK RX/TX and 2FSK TX. At some point I'll be working on 2FSK RX (with non-standard preamble and whitening polynomial not supported by 446x) so that will take some fiddling with pre-amble detection and non-standard PH processing.
Continued in next post... |
Jan 09 2019, 4:57 AM |

Robert Anderson |
Updated
to
AFSK signal demodulation with EZRadioPro
Part II of my reply...
Good to know that was already correct.
Thank you for the information on how to get the result required from WDS.
I found a formula in the API docs and an EZR Reference Manual(s) for expressing RSSI in dBM. This was dBm = ((RSSI / 2) - Si446x_MODEM_RSSI_COMP_VALUE - 70). For this next formula the default for MODEM_RSSI_COMP is 64 so 70 + 64 = 134 which is different to the 130 in the first formula.
I have code that calculates and sets the IF_FREQ as required using the formulas in the API docs. However, there is no formula for calculating FREQ_CONTROL_VCOCNT_RX_ADJ in the API docs. Is my deduced formula correct?
Thanks
Robert |
Jan 09 2019, 12:24 AM |

Robert Anderson |
Updated
to
AFSK signal demodulation with EZRadioPro
Part II of my reply...
Good to know that was already correct.
Thank you for the information on how to get the result required from WDS. However, It should be possible for 2FSK so I will definitely produce some coefficients and give gear switching a test for 2FSK RX try when I get to that stage.
I found a formula in the API docs and an EZR Reference Manual(s) for expressing RSSI in dBM. This was dBm = ((RSSI / 2) - Si446x_MODEM_RSSI_COMP_VALUE - 70).
I have code that calculates and sets the IF_FREQ as required using the formulas in the API docs. However, there is no formula for calculating FREQ_CONTROL_VCOCNT_RX_ADJ in the API docs. Is my deduced formula correct?
Thanks
Robert |
Jan 08 2019, 11:27 PM |

Robert Anderson |
Updated
to
AFSK signal demodulation with EZRadioPro
Part II of my reply...
Good to know that was already correct.
Thank you for the information on how to get the result required from WDS. However, It should be possible for 2FSK so I will definitely produce some coefficients and give gear switching a for 2FSK RX try when I get to that stage.
I found a formula in the API docs and an EZR Reference Manual(s) for expressing RSSI in dBM. This was dBm = ((RSSI / 2) - Si446x_MODEM_RSSI_COMP_VALUE - 70).
I have code that calculates and sets the IF_FREQ as required using the formulas in the API docs. However, there is no formula for calculating FREQ_CONTROL_VCOCNT_RX_ADJ in the API docs. Is my deduced formula correct?
Thanks
Robert |
Jan 08 2019, 11:27 PM |