[参考译文] CC1120：在接收模式下、即使没有 RF 信号出现、RSSI 值仍为高电平

https://e2e.ti.com/support/wireless-connectivity/sub-1-ghz-group/sub-1-ghz/f/sub-1-ghz-forum/1234120/cc1120-in-reception-mode-even-if-there-is-no-rf-signal-present-the-rssi-value-is-still-high

这是 SmartRF Studio 生成的寄存器配置。

// Address Config = No address check 
// Bit Rate = 1.2 
// Carrier Frequency = 434.000000 
// Deviation = 3.997803 
// Device Address = 0 
// Manchester Enable = false 
// Modulation Format = 2-FSK 
// PA Ramping = true 
// Packet Bit Length = 0 
// Packet Length = 255 
// Packet Length Mode = Variable 
// Performance Mode = High Performance 
// RX Filter BW = 10.000000 
// Symbol rate = 1.2 
// TX Power = 15 
// Whitening = false 
#include "stdint.h"
const uint16_t CC112X_REG_SETTING[][2]= 
{
 {0X0000,0X53},//IOCFG3            GPIO3 IO PIN CONFIGURATION
 {0X0001,0X46},//IOCFG2            GPIO2 IO PIN CONFIGURATION
 {0X0003,0X51},//IOCFG0            GPIO0 IO PIN CONFIGURATION
 {0X0008,0X0B},//SYNC_CFG1         SYNC WORD DETECTION CONFIGURATION REG. 1
 {0X000C,0X1C},//DCFILT_CFG        DIGITAL DC REMOVAL CONFIGURATION
 {0X0010,0XC6},//IQIC              DIGITAL IMAGE CHANNEL COMPENSATION CONFIGURATION
 {0X0013,0X05},//MDMCFG0           GENERAL MODEM PARAMETER CONFIGURATION REG. 0
 {0X0017,0X20},//AGC_REF           AGC REFERENCE LEVEL CONFIGURATION
 {0X0018,0X19},//AGC_CS_THR        CARRIER SENSE THRESHOLD CONFIGURATION
 {0X001C,0XA9},//AGC_CFG1          AUTOMATIC GAIN CONTROL CONFIGURATION REG. 1
 {0X001D,0XCF},//AGC_CFG0          AUTOMATIC GAIN CONTROL CONFIGURATION REG. 0
 {0X001E,0X00},//FIFO_CFG          FIFO CONFIGURATION
 {0X0021,0X14},//FS_CFG            FREQUENCY SYNTHESIZER CONFIGURATION
 {0X0028,0X20},//PKT_CFG0          PACKET CONFIGURATION REG. 0
 {0X002E,0XFF},//PKT_LEN           PACKET LENGTH CONFIGURATION
 {0X2F00,0X00},//IF_MIX_CFG        IF MIX CONFIGURATION
 {0X2F01,0X22},//FREQOFF_CFG       FREQUENCY OFFSET CORRECTION CONFIGURATION
 {0X2F0C,0X6C},//FREQ2             FREQUENCY CONFIGURATION [23:16]
 {0X2F0D,0X80},//FREQ1             FREQUENCY CONFIGURATION [15:8]
 {0X2F12,0X00},//FS_DIG1           FREQUENCY SYNTHESIZER DIGITAL REG. 1
 {0X2F13,0X5F},//FS_DIG0           FREQUENCY SYNTHESIZER DIGITAL REG. 0
 {0X2F16,0X40},//FS_CAL1           FREQUENCY SYNTHESIZER CALIBRATION REG. 1
 {0X2F17,0X0E},//FS_CAL0           FREQUENCY SYNTHESIZER CALIBRATION REG. 0
 {0X2F19,0X03},//FS_DIVTWO         FREQUENCY SYNTHESIZER DIVIDE BY 2
 {0X2F1B,0X33},//FS_DSM0           FS DIGITAL SYNTHESIZER MODULE CONFIGURATION REG. 0
 {0X2F1D,0X17},//FS_DVC0           FREQUENCY SYNTHESIZER DIVIDER CHAIN CONFIGURATION ..
 {0X2F1F,0X50},//FS_PFD            FREQUENCY SYNTHESIZER PHASE FREQUENCY DETECTOR CON..
 {0X2F20,0X6E},//FS_PRE            FREQUENCY SYNTHESIZER PRESCALER CONFIGURATION
 {0X2F21,0X14},//FS_REG_DIV_CML    FREQUENCY SYNTHESIZER DIVIDER REGULATOR CONFIGURAT..
 {0X2F22,0XAC},//FS_SPARE          FREQUENCY SYNTHESIZER SPARE
 {0X2F27,0XB4},//FS_VCO0           FS VOLTAGE CONTROLLED OSCILLATOR CONFIGURATION REG..
 {0X2F32,0X0E},//XOSC5             CRYSTAL OSCILLATOR CONFIGURATION REG. 5
 {0X2F36,0X03},//XOSC1             CRYSTAL OSCILLATOR CONFIGURATION REG. 1
 {0XFFFF,0XFF}
};

在我的实际测试后、即使在连接天线时没有射频信号源、读取的 RSSI 值也高达-75dbm、在该值附近波动。 当我拔下天线时、RSSI 值降到-100dBm 左右、显然是无信号时的正常值。 我已经使用软件对 RSSI 值进行了补偿。 当我使用仪器输入不同强度的射频信号时、读取的 RSSI 值是正常的、RSSI 值与仪器的输出强度之间的误差在3dBm 以内。 这应该表明 RSSI 指示寄存器没有问题。 问题是：为什么没有射频信号时 RSSI 值读数这么高？ 请问是什么原因造成了这种情况，如何加以改进？ 此问题对接收性能有重大影响

此外、我已尝试在 SmartRF Studio 中使用不同的射频参数设置、未进行任何更改或改进。