why are the IQ values of nrf5340DK so small? AOA

[yntense]

rssi	i	q
-63	0	0
-63	44	-45
-63	-8	11
-63	-45	45
-63	9	-12
-63	46	-46
-63	-12	14
-63	-46	-21
-63	41	-36
-63	31	-45
-63	16	-47
-63	-3	-42
-63	-22	-31
-63	-36	-14
-63	-45	4
-63	-47	22
-63	-45	38
-63	-47	48
-63	-54	58
-63	-55	68
-63	-40	73
-63	-11	71
-63	23	59
-63	51	41
-63	61	18
-63	47	-6
-63	17	-25
-63	-14	-32
-63	-37	-23
-63	-45	-4
-63	-45	16
-63	-41	21
-63	-35	4
-63	-18	-26
-63	7	-53
-63	24	-69
-63	21	-68
-63	1	-57
-63	-28	-40
-63	-52	-31
-63	-65	-32
-63	-62	-40
-63	-51	-43
-63	-43	-35
-63	-41	-15
-63	-47	8
-63	-52	26
-63	-48	34
-63	-40	34
-63	-39	26
-63	-50	21
-63	-61	25
-63	-62	39
-63	-46	57
-63	-22	66
-63	2	59
-63	13	37
-63	5	7
-63	-16	-15
-63	-37	-20
-63	-51	-8
-63	-51	14
-63	-45	32
-63	-37	42
-63	-25	43
-63	-9	40
-63	12	33
-63	28	17
-63	40	-2
-63	44	-21
-63	38	-35
-63	26	-44
-63	9	-47
-63	-8	-40
-63	-24	-29
-63	-38	-13
-63	-45	5
-63	-47	22
-63	-41	37
-63	-30	49
-63	-18	63
-63	-13	74
-63	-13	82
-63	-8	81
-63	7	71
-63	32	50
-63	58	26
-63	74	4
-63	73	-9
-63	50	-12
-63	13	-9
-63	-24	1
-63	-46	12
-63	-47	27
-63	-32	40
-63	-17	41
-63	-8	17
-63	-8	-21
-63	-12	-52
-63	-19	-62
-63	-33	-48
-63	-48	-21
-63	-60	4
-63	-68	18
-63	-70	13
-63	-68	0
-63	-64	-10
-63	-59	-7
-63	-55	12
-63	-47	34
-63	-35	48

but at the same position, when I used NRF52833， I got the following result！so， why are the IQ values of nrf5340DK  so small? 

rssi	i	q
-54	196	51
-54	-58	190
-54	-197	-55
-54	52	-195
-54	197	34
-54	-31	194
-54	-200	-31
-54	-15	-211
-54	80	85
-54	-11	84
-54	-111	65
-54	-186	29
-54	-211	-22
-54	-186	-85
-54	-131	-149
-54	-76	-192
-54	-22	-190
-54	44	-146
-54	114	-85
-54	165	-20
-54	178	40
-54	155	93
-54	101	140
-54	38	173
-54	-19	183
-54	-75	166
-54	-132	130
-54	-181	81
-54	-206	19
-54	-201	-53
-54	-166	-126
-54	-128	-176
-54	-123	-153
-54	-150	-43
-54	-187	84
-54	-220	150
-54	-235	114
-54	-234	2
-54	-220	-117
-54	-198	-182
-54	-189	-161
-54	-197	-62
-54	-213	45
-54	-227	97
-54	-225	64
-54	-206	-36
-54	-178	-140
-54	-147	-190
-54	-122	-174
-54	-104	-118
-54	-91	-63
-54	-77	-30
-54	-53	-30
-54	-24	-56
-54	-3	-76
-54	2	-68
-54	-18	-28
-54	-64	37
-54	-124	96
-54	-178	120
-54	-206	89
-54	-209	9
-54	-194	-82
-54	-170	-144
-54	-132	-147
-54	-73	-96
-54	-7	-28
-54	37	32
-54	48	66
-54	30	71
-54	-7	65
-54	-45	69
-54	-72	96
-54	-94	134
-54	-121	160
-54	-156	157
-54	-189	111
-54	-212	32
-54	-212	-54
-54	-190	-120
-54	-171	-157
-54	-178	-164
-54	-198	-160
-54	-197	-163
-54	-150	-186
-54	-61	-221
-54	35	-237
-54	96	-213
-54	85	-136
-54	16	-19
-54	-71	89
-54	-145	144
-54	-184	123
-54	-191	40
-54	-186	-58
-54	-173	-125
-54	-141	-136
-54	-80	-104
-54	-9	-60
-54	45	-18
-54	75	9
-54	77	24
-54	58	38
-54	29	65
-54	4	108
-54	-18	156
-54	-49	189
-54	-94	195
-54	-144	164
-54	-185	98
-54	-207	13
-54	-203	-55
-54	-181	-60
-54	-137	21
-54	-86	140
-54	-64	232
-54	-84	246
-54	-143	184
-54	-212	96
-54	-250	43
-54	-231	67
-54	-162	140
-54	-95	211
-54	-76	237
-54	-110	199
-54	-173	113
-54	-222	20
-54	-230	-43
-54	-214	-47
-54	-201	18
-54	-202	112
-54	-216	173
-54	-232	150
-54	-246	50
-54	-247	-69
-54	-227	-139
-54	-192	-117
-54	-148	-10
-54	-112	121
-54	-99	212
-54	-115	221
-54	-158	150
-54	-206	54
-54	-231	-10
-54	-209	-19
-54	-143	10
-54	-68	42
-54	-19	66
-54	-6	69
-54	-22	47
-54	-49	24
-54	-62	17
-54	-55	41
-54	-38	97
-54	-28	163
-54	-40	213
-54	-79	213
-54	-138	157
-54	-196	74
-54	-225	8
-54	-217	-10
-54	-175	19
-54	-126	59
-54	-94	80
-54	-84	63
-54	-91	13
-54	-99	-37
-54	-92	-58
-54	-72	-28
-54	-42	52
-54	-17	146
-54	-19	211
-54	-52	220
-54	-111	172
-54	-175	96
-54	-215	35
-54	-224	14
-54	-213	37
-54	-200	74
-54	-195	89
-54	-193	55
-54	-185	-25
-54	-162	-110
-54	-125	-155
-54	-88	-123
-54	-50	-18
-54	-22	111
-54	-18	207
-54	-43	232
-54	-97	188
-54	-162	115
-54	-210	56
-54	-220	24
-54	-202	2
-54	-177	-26
-54	-148	-59
-54	-110	-97
-54	-61	-136
-54	-6	-154
-54	45	-139
-54	74	-82
-54	79	13
-54	63	114
-54	27	188
-54	-25	213
-54	-88	186
-54	-152	134
-54	-196	81
-54	-192	32
-54	-146	-36
-54	-85	-112
-54	-25	-171
-54	27	-191
-54	77	-171
-54	124	-121
-54	162	-58
-54	178	3
-54	167	62

[Einarh]

Hello

What software version are you using?

Best regards,

Einar

[yntense]

ncs_v1.9.1

[Einarh]

I've asked the direction finding team about this internally, you can expect an answer next week.

-Einar

[yntense]

thanks

[Einarh]

Hello!

In NCS 1.9.1, there is a 4 bit left shift applied to IQ samples on the nRF5340 and nRF52833. But since the nRF5340 has a 9-bit internal ADC while the nRF52833 has a 12-bit internal ADC, this bit shift affects the magnitude of the IQ samples on the nRF5340 more. This issue has been fixed in upstream Zephyr, so the fix will be included in the next NCS release.

Though even when this issue is dealt with, there may still be differences in the values because of physical differences between the SOCs such as the AGC and the radio peripheral.

Best regards,

Einar