这一影响减到最小。
RF 与 IF 迹线应尽可能十字交*,并尽可能在它们之间隔一块地。正确的 RF 路径对整块 PCB
的性能非常重要,这就是元器件布局通常在蜂窝电话
PCB
设计中占大部分时间的原因。
(4)降低高/低功率器件干扰耦合的设计原则。在蜂窝电话 PCB 上,通常可以将低噪音放大器电路放在 PCB 的
某一面
,而将高功率放大器放在另一面,并最终通过双工器把它们在同一面上连接到 RF 端和基带处理器端的天线上。
要用技巧来确保通孔不会把
RF 能量从板的一面传递到另一面,常用的技术是在二面都使用盲孔。可以通过将通孔
安排在
PCB 板二面都不受 RF 干扰的区域来将通孔的不利影响减到最小。
void IA4432_Init(void)
{
IA4432_Register((REG_WRITE | OperatingFunctionControl1), 0x80);
IA4432_Register((REG_WRITE | TXRampControl), 0x7F);
IA4432_Register((REG_WRITE | AFCLoopGearshiftOverride), 0x00);
IA4432_Register((REG_WRITE | FrequencyBandSelect), 0x53); //set frequency
IA4432_Register((REG_WRITE | NominalCarrierFrequency1), 0x4b); //433HZ
IA4432_Register((REG_WRITE | NominalCarrierFrequency0), 0x00);
IA4432_Register((REG_WRITE | ModulationModeControl1), 0x00);
IA4432_Register((REG_WRITE | ModulationModeControl2), 0x22); //asynchronous mode
FSK
IA4432_Register((REG_WRITE | HeaderControl2), 0x02); //no head; sync word 3 and 2
IA4432_Register((REG_WRITE | HeaderControl1), 0x00);
IA4432_Register((REG_WRITE | PreambleLength), 0x04); //2byte
IA4432_Register((REG_WRITE | PreambleDetectionControl), 0x10); //8bit
IA4432_Register((REG_WRITE | SyncWord3), 0x2d);
IA4432_Register((REG_WRITE | SyncWord2), 0xd4);
//IA4432_Register((REG_WRITE | TransmitPacketLength), 0x40);
IA4432_Register((REG_WRITE | DataAccessControl), 0x88); //enable TX handling
IA4432_Register((REG_WRITE | IFFilterBandwidth), 0x03); //BW=90kHZ
IA4432_Register((REG_WRITE | ClockRecoveryOversamplingRatio), 0xa1);
IA4432_Register((REG_WRITE | ClockRecoveryOffset2), 0x20);
IA4432_Register((REG_WRITE | ClockRecoveryOffset1), 0x4e);
IA4432_Register((REG_WRITE | ClockRecoveryOffset0), 0xa5);
IA4432_Register((REG_WRITE | ClockRecoveryTimingLoopGain1), 0x00);
IA4432_Register((REG_WRITE | ClockRecoveryTimingLoopGain0), 0x36);
IA4432_Register((REG_WRITE | TXDataRate1), 0x02); //9600BPS
IA4432_Register((REG_WRITE | TXDataRate0), 0x75);
IA4432_Register((REG_WRITE | FrequencyDeviation), 0x48);
IA4432_Register((REG_WRITE | ClockRecoveryGearshiftOverride), 0x13);
IA4432_Register((REG_WRITE | GPIO0Configuration), 0x1f);
IA4432_Register((REG_WRITE | GPIO1Configuration), 0x12); //GPIO_1 TX state
IA4432_Register((REG_WRITE | GPIO2Configuration), 0x15); //GPIO_2 RX state
IA4432_Register((REG_WRITE | OperatingFunctionControl2), 0x02);
IA4432_Register((REG_WRITE | OperatingFunctionControl2), 0x00);
IA4432_Register((REG_WRITE | InterruptEnable1), 0x02);
}
void RF_R(unsigend char *d)
{
unsigned char index,yyy,ttt;
IA4432_Register((REG_WRITE | OperatingFunctionControl2), 0x02);
IA4432_Register((REG_WRITE | OperatingFunctionControl2), 0x00);
IA4432_Register((REG_WRITE | OperatingFunctionControl1), 0x05);
while(1)
{
yyy = IA4432_Register((REG_READ | InterruptStatus1),0x00);
if(yyy&0x02) break;
}
IA4432_Register((REG_WRITE | OperatingFunctionControl1), 0x01);