关于per的问题，请帮忙分析

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Software version : v2.0.3 (30 days trial version)
IP Address : 192.168.100.254
Interface type : TCPIP
Interface Port :
Log all : Enabled - no signal file
Log fail : Enabled - no signal file
IQ Flow File : IQ_Flow_TEST.txt
IQ DUT File : IQ_DUT_Chipset.txt
MAC Assign Method: Read from barcode reader, pass only
Serial no. Method: Use date and time
Failure Handling : Stop
Product ID : RTL8196C
Station ID : 0011
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Current time : Mon Nov 21 10:26:07 2011
Illegal command in flow file : 'IQ_RX_VERIFY_START '
Illegal command in flow file : 'IQ_RX_VERIFY_END'
Illegal command in flow file : ' IQ_CAL_TX_OUTPUT '
Illegal command in flow file : 'WRITE_EEPROM_START'
Illegal command in flow file : 'WRITE_EEPROM_END'
Illegal command in flow file : 'IQ_TX_VERIFY_START '
Illegal command in flow file : 'IQ_TX_VERIFY_END'
Illegal command in flow file : 'WRITE_EEPROM_START'
Illegal command in flow file : 'WRITE_EEPROM_END'
illegal command 'IQ_FIXED_ATTEN_2_4_CHAIN3' at attenuation setup file!
illegal command 'IQ_FIXED_ATTEN_5_CHAIN3' at attenuation setup file!
IQ Tester Initialize
IQ API Version:
IQmeasure: 1.7.13.0 (2009-10-14)
iqapi: 1.7.48 (Dec 9 2009)
iqapitc: 1.2.39 Dec 2 2009
iq_nxn: 1.1.7a (2009-11-20)
IQV_mw: 3.2.5g Jul 24 2009 Tester 1
SN: IQF09663
iq_nxn_signal: 1.1.15 (2009-09-24)
iq_max_signal: 1.0.46 (2008-08-26)
iq_zigbee_signal: 1.0.8 (2009-10-20)
iq_nfc_signal: 0.2.19 (2009-09-11)
bluetooth: 1.1.2.h December 8 2009
iqv_analysis: 1.4.1.b Sept 24 2009
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Current time : Mon Nov 21 10:26:20 2011
Serial no. : 111121-102620
1 . IQ_INITIALIZE_TESTER EC:T0109 ____________________________________________
Test Time = 0.015 sec
2 . IQ_OBTAIN_CONTROL EC:T0109 _______________________________________________
Test Time = 1.860 sec
3 . IQ_INSERT_DUT EC:T0191 ___________________________________________________
Test Time = 0.000 sec
4 . IQ_INITIALIZE_DUT EC:T0191 _______________________________________________
tftp -i 192.168.10.1 put nfjrom
>> Timeout occurred
API: OpenDUT
API: StartTest
RF Type: 2T2R
Test Time = 20.547 sec
5 . IQ_VERIFY_RX_PER 2442 11M ANT1 EC:T0040 __________________________________
API: StartRxPacket
Num_Frames:500
Num_Packet_OK:500
Num_Packet_Err:0
API: StopRxPacket
PER @ -82dBm : 0.00% ( 0.00 *................. 8.00)
Test Time = 1.562 sec
6 . IQ_VERIFY_RX_PER 2442 11M ANT2 EC:T0040 __________________________________
API: StartRxPacket
Num_Frames:500
Num_Packet_OK:416
Num_Packet_Err:84
API: StopRxPacket
API: StartRxPacket
Num_Frames:500
Num_Packet_OK:432
Num_Packet_Err:68
API: StopRxPacket
API: StartRxPacket
Num_Frames:500
Num_Packet_OK:416
Num_Packet_Err:84
API: StopRxPacket
API: StartRxPacket
Num_Frames:500
Num_Packet_OK:408
Num_Packet_Err:92
API: StopRxPacket
API: StartRxPacket
Num_Frames:500
Num_Packet_OK:418
Num_Packet_Err:82
API: StopRxPacket
API: StartRxPacket
Num_Frames:500
Num_Packet_OK:401
Num_Packet_Err:99
API: StopRxPacket
PER @ -82dBm : 19.80% ( 0.00 .................X 8.00)
Test Time = 4.844 sec
**************************************************************
Test aborted by 'STOP ON FAIL' setting!
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50. IQ_RELEASE_CONTROL EC:T0109 ______________________________________________
Test Time = 0.125 sec
51. IQ_REMOVE_DUT EC:T0191 ___________________________________________________
CloseDutConnection
API: StopTest
API: CloseDUT
Test Time = 1.437 sec
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Test Time Summary
=================
1 . IQ_INITIALIZE_TESTER EC:T0109 : 0.01 sec
2 . IQ_OBTAIN_CONTROL EC:T0109 : 1.86 sec
3 . IQ_INSERT_DUT EC:T0191 : 0.00 sec
4 . IQ_INITIALIZE_DUT EC:T0191 :20.55 sec
5 . IQ_VERIFY_RX_PER 2442 11M ANT1 EC:T0040 0.00: 1.56 sec
6 . IQ_VERIFY_RX_PER 2442 11M ANT2 EC:T0040 19.80: 4.84 sec
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Total Test Time : 28.52 sec
IQ Tester Usage Time: 28.52 sec
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**** F A I L ****
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Please remove DUT, press any key to continue OR 'X' key to exit........
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当把RF部分铁盖盖上时，测试结果如上，拆下时测试pass，为什么啊？

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