CC1200 sensitivity

Sargis Sargsyan

Other Parts Discussed in Thread: CC1200

I have a problem with sensitivity level of CC1200. I'm using standard CC1200 Evaluation Module Kit 868-930MHz but for 38.ksps and 4GFSK modulation with deviation 20KHz have a -100dbm sensitivity level at 920 MHz, bellow is the configuration witche generated in Smart RF studio

{IOCFG3, 0x06},

{IOCFG2, 0x06},

{IOCFG1, 0x30},

{IOCFG0, 0x3C},

{SYNC3, 0x93},

{SYNC2, 0x0B},

{SYNC1, 0x51},

{SYNC0, 0xDE},

{SYNC_CFG1, 0xA8},

{SYNC_CFG0, 0x03},

{DEVIATION_M, 0x06},

{MODCFG_DEV_E, 0x2B},

{DCFILT_CFG, 0x4C},

{PREAMBLE_CFG1, 0x14},

{PREAMBLE_CFG0, 0x8A},

{IQIC, 0x48},

{CHAN_BW, 0x84},

{MDMCFG1, 0x42},

{MDMCFG0, 0x05},

{SYMBOL_RATE2, 0x8F},

{SYMBOL_RATE1, 0x75},

{SYMBOL_RATE0, 0x10},

{AGC_REF, 0x27},

{AGC_CS_THR, 0x01},

{AGC_GAIN_ADJUST, 0x00},

{AGC_CFG3, 0xB1},

{AGC_CFG2, 0x20},

{AGC_CFG1, 0x11},

{AGC_CFG0, 0x94},

{FIFO_CFG, 0x00},

{DEV_ADDR, 0x00},

{SETTLING_CFG, 0x0B},

{FS_CFG, 0x12},

{WOR_CFG1, 0x08},

{WOR_CFG0, 0x21},

{WOR_EVENT0_MSB, 0x00},

{WOR_EVENT0_LSB, 0x00},

{RXDCM_TIME, 0x00},

{PKT_CFG2, 0x00},

{PKT_CFG1, 0x03},

{PKT_CFG0, 0x20},

{RFEND_CFG1, 0x0F},

{RFEND_CFG0, 0x00},

{PA_CFG1, 0x7F},

{PA_CFG0, 0x56},

{ASK_CFG, 0x0F},

{PKT_LEN, 0xFF},

{IF_MIX_CFG, 0x1C},

{FREQOFF_CFG, 0x20},

{TOC_CFG, 0x03},

{MARC_SPARE, 0x00},

{ECG_CFG, 0x00},

{MDMCFG2, 0x02},

{EXT_CTRL, 0x01},

{RCCAL_FINE, 0x00},

{RCCAL_COARSE, 0x00},

{RCCAL_OFFSET, 0x00},

{FREQOFF1, 0x00},

{FREQOFF0, 0x00},

{FREQ2, 0x5C},

{FREQ1, 0x0F},

{FREQ0, 0x5C},

{IF_ADC2, 0x02},

{IF_ADC1, 0xEE},

{IF_ADC0, 0x10},

{FS_DIG1, 0x04},

{FS_DIG0, 0x55},

{FS_CAL3, 0x00},

{FS_CAL2, 0x20},

{FS_CAL1, 0x40},

{FS_CAL0, 0x0E},

{FS_CHP, 0x28},

{FS_DIVTWO, 0x03},

{FS_DSM1, 0x00},

{FS_DSM0, 0x33},

{FS_DVC1, 0xFF},

{FS_DVC0, 0x17},

{FS_LBI, 0x00},

{FS_PFD, 0x00},

{FS_PRE, 0x6E},

{FS_REG_DIV_CML, 0x1C},

{FS_SPARE, 0xAC},

{FS_VCO4, 0x14},

{FS_VCO3, 0x00},

{FS_VCO2, 0x00},

{FS_VCO1, 0x00},

{FS_VCO0, 0xB5},

{GBIAS6, 0x00},

{GBIAS5, 0x02},

{GBIAS4, 0x00},

{GBIAS3, 0x00},

{GBIAS2, 0x10},

{GBIAS1, 0x00},

{GBIAS0, 0x00},

{IFAMP, 0x09},

{LNA, 0x01},

{RXMIX, 0x01},

{XOSC5, 0x0E},

{XOSC4, 0xA0},

{XOSC3, 0x03},

{XOSC2, 0x04},

{XOSC1, 0x03},

{XOSC0, 0x00},

{ANALOG_SPARE, 0x00},

{PA_CFG3, 0x00},

{WOR_TIME1, 0x00},

{WOR_TIME0, 0x00},

{WOR_CAPTURE1, 0x00},

{WOR_CAPTURE0, 0x00},

{BIST, 0x00},

{DCFILTOFFSET_I1, 0x00},

{DCFILTOFFSET_I0, 0x00},

{DCFILTOFFSET_Q1, 0x00},

{DCFILTOFFSET_Q0, 0x00},

{IQIE_I1, 0x00},

{IQIE_I0, 0x00},

{IQIE_Q1, 0x00},

{IQIE_Q0, 0x00},

{RSSI1, 0x80},

{RSSI0, 0x00},

{MARCSTATE, 0x41},

{LQI_VAL, 0x00},

{PQT_SYNC_ERR, 0xFF},

{DEM_STATUS, 0x00},

{FREQOFF_EST1, 0x00},

{FREQOFF_EST0, 0x00},

{AGC_GAIN3, 0x00},

{AGC_GAIN2, 0xD1},

{AGC_GAIN1, 0x00},

{AGC_GAIN0, 0x3F},

{CFM_RX_DATA_OUT, 0x00},

{CFM_TX_DATA_IN, 0x00},

{ASK_SOFT_RX_DATA,0x30},

{RNDGEN, 0x7F},

{MAGN2, 0x00},

{MAGN1, 0x00},

{MAGN0, 0x00},

{ANG1, 0x00},

{ANG0, 0x00},

{CHFILT_I2, 0x02},

{CHFILT_I1, 0x00},

{CHFILT_I0, 0x00},

{CHFILT_Q2, 0x00},

{CHFILT_Q1, 0x00},

{CHFILT_Q0, 0x00},

{GPIO_STATUS, 0x00},

{FSCAL_CTRL, 0x01},

{PHASE_ADJUST, 0x00},

{PARTNUMBER, 0x00},

{PARTVERSION, 0x00},

{SERIAL_STATUS, 0x00},

{MODEM_STATUS1, 0x01},

{MODEM_STATUS0, 0x00},

{MARC_STATUS1, 0x00},

{MARC_STATUS0, 0x00},

{PA_IFAMP_TEST, 0x00},

{FSRF_TEST, 0x00},

{PRE_TEST, 0x00},

{PRE_OVR, 0x00},

{ADC_TEST, 0x00},

{DVC_TEST, 0x0B},

{ATEST, 0x40},

{ATEST_LVDS, 0x00},

{ATEST_MODE, 0x00},

{XOSC_TEST1, 0x3C},

{XOSC_TEST0, 0x00},

{AES, 0x00},

{MDM_TEST, 0x00},

{RXFIRST, 0x00},

{TXFIRST, 0x00},

{RXLAST, 0x00},

{TXLAST, 0x00},

{NUM_TXBYTES, 0x00},

{NUM_RXBYTES, 0x00},

{FIFO_NUM_TXBYTES,0x0F},

{FIFO_NUM_RXBYTES,0x00},

{RXFIFO_PRE_BUF, 0x00},

{AES_KEY15, 0x00},

{AES_KEY14, 0x00},

{AES_KEY13, 0x00},

{AES_KEY12, 0x00},

{AES_KEY11, 0x00},

{AES_KEY10, 0x00},

{AES_KEY9, 0x00},

{AES_KEY8, 0x00},

{AES_KEY7, 0x00},

{AES_KEY6, 0x00},

{AES_KEY5, 0x00},

{AES_KEY4, 0x00},

{AES_KEY3, 0x00},

{AES_KEY2, 0x00},

{AES_KEY1, 0x00},

{AES_KEY0, 0x00},

{AES_BUFFER15, 0x00},

{AES_BUFFER14, 0x00},

{AES_BUFFER13, 0x00},

{AES_BUFFER12, 0x00},

{AES_BUFFER11, 0x00},

{AES_BUFFER10, 0x00},

{AES_BUFFER9, 0x00},

{AES_BUFFER8, 0x00},

{AES_BUFFER7, 0x00},

{AES_BUFFER6, 0x00},

{AES_BUFFER5, 0x00},

{AES_BUFFER4, 0x00},

{AES_BUFFER3, 0x00},

{AES_BUFFER2, 0x00},

{AES_BUFFER1, 0x00},

{AES_BUFFER0, 0x00},

If I'm not wrong with this configurations the receiver in the worst case should be provide -109dbm sensitivity. My question is: Am I in misunderstand with datasheet or some important registers configured not correctly.

Thanks in Advance

over 9 years ago

0 TA12012 over 9 years ago

TI__Mastermind 36395 points

What is the criteria that you have used to define the sensitivity limit?

Regards,
/TA

0 TER over 9 years ago in reply to TA12012

TI__Guru**** 317180 points

On CC1200 the deviation is given for the outer symbols. That means that for 20 kHz deviation the inner symbols is 6.7 kHz which gives poor modulation index given the 38.4 ksps. To get better sensitivity you can try to increase the deviation some.

The test system is in use so I don't have the opportunity to test with your settings.

0 Sargis Sargsyan over 9 years ago in reply to TER

Intellectual 375 points

HI TER,
Thank you for response. Now I'm testing 38.4 ksps 2GFSK ,19.2kHz deviation with RX bandwidth 100 kHz but sensitivity is still poor -107 dbm. The values for configuration given from Smart RF studio for 928 MHz, did you ever tested that settings ? And if yes how is the sensitivity level ?

Thanks in Advance

0 Sargis Sargsyan over 9 years ago in reply to TA12012

Intellectual 375 points

Hi TA,
In the datasheet written that for 50Kbps sensitivity is about -109dbm and that mean for 38.4 kbps sensitivity mast be at least -109.

0 TER over 9 years ago in reply to Sargis Sargsyan

TI__Guru**** 317180 points

From the lab measurements we have done:
Sensitivity @868.3 MHz, 38.4 kbps: -109.8 dBm.
From a sweep checking sensitivity vs frequency: The sensitivity is between 0.5 and 1.0 dB higher on 928 MHz compared to 868.3 MHz meaning that your result is about 1.5 - 2.0 dB from our results. This is very close to the expected variation from chip to chip.

- Do you measure with 3 byte payload and 20 % PER?
- Do you have a fully calibrated test system?

0 Sargis Sargsyan over 9 years ago in reply to TER

Intellectual 375 points

TER,
About measurements yes I'm tested with 3 byte payload and 20% per. But about your second question what did you mean when say fully calibrated test system?

0 TER over 9 years ago in reply to Sargis Sargsyan

TI__Guru**** 317180 points

Basically that you have accounted for all loss in cables etc. We use an VNA to find the exact transfer function for the path between the generator and the DUT.

How does you test setup look like?

0 Sargis Sargsyan over 9 years ago in reply to TER

Intellectual 375 points

Oh yes. I'm takes in account all possible factors which can affect on receiver. Did you know how can enabling of FEC improve sensitivity? And I'm can't find information about redundant of FEC.

0 TER over 9 years ago in reply to Sargis Sargsyan

TI__Guru**** 317180 points

FEC does not improve sensitivity in a controlled environment. FEC introduce some redundancy which makes a more robust link since bit errors due to noise can be corrected to some degree.

How to enable the FEC is in the UserGuide.

0 Sargis Sargsyan over 9 years ago in reply to TER

Intellectual 375 points

in user's guide i'm find out that CC1200 has Viterbi detection, in my configuration FEC disabled but Viterbi is on moreover receiver work correctly. It is ok ? CC1200 doing convolution codding in transmitter side ?

0 TER over 9 years ago in reply to Sargis Sargsyan

TI__Guru**** 317180 points

Ye, the viterbi is on default and this gives the best sensitivity.

Sub-1 GHz

Sub-1 GHz forum

CC1200 sensitivity