Hewlett Packard 83220E

Reverse Engineering - Hewlett Packard 83220E

I bought my unit some long time ago which was declared as not operational (as a package with HP 8922M) but as I tested it I could not find any problem with it at all. All of the internal tests did run just fine and I was able to establish GSM connection with a cell phone or even listen to local FM radio :)
Since I also have an SDR, I have not really a use for this unit. I did use it a few times as a RF signal generator, since I don't own a "proper" RF signal generator but not for more. One option would be to try and sell it, but the market is almost flooded with such units that I will not try my luck. Another option is to tear it down, reverse engineer it, see how the HP engineers did design this unit, learn something and maybe re-purpose it.
Motivation for reverse engineering such a device is curiosity and lack of official information about functional principle.
One could guess how the device does work. Since it is an add-on to the HP 8922 for DCS1800 or PCS1900  band extension it will probably only up/down-convert and level the signal generated by the HP 8922.

Overview

The unit does operate within 1710 to 1990 MHz and my unit does have following data:
Ser: 3741U02387
OPT: 010

Inside the unit there are not so many components and some of them are standard microwave components from shelf.

Inside view of HP 83220E

On the top side is the control electronics.
On the right side is the power supply section, behind aluminium covers.
Generated Voltages are as follow:
+15V_att
+15V
-15V
+5.2V
On the bottom side are three main modules, which will be investigated more in detail.

Block Diagram

It was very easy to track down the semi-rigid cables and draw a block diagram of the unit, which can be seen above.

Output Section

xxx

Output Section PCB

Description and Block diagram: TODO

Flat Cable

	Output Section
Pin	Description
1	15V
2	15V
3	-15V
4	5.2V
5	GND
6	GND
7	AM/LEVEL REF
8	GND
9	GND
10	P1
11	P2
12	P3
13	GND
14	NC
15	ALC OOL (L)
16	GND
17	GND
18	GND
19	GND
20	GND

Receiver Detector

xxx

Receiver and Detector PCB

Description and Block diagram: TODO

Receiver Detector Block Diagram

Flat Cable

	Receiver Detector
Pin	Description	1800	1900	900	835
1	15V
2	15V
3	-15V
4	5.2V
5	IN GND NC / NP
6	IN GND NC / NP
7	R87 --> TL074 (8,9) OUT	0.309	0.3	0	0
8	IN 5.2V NC / NP
9	GND
10	IN GND NC / NP
11	OUT LM35 temp	0.358	0.365	0.367	0.367
12	IN TL072 (5) 7k5, 3k83 GND	1V, 1.524V	1.4V, 2.191V	2.6V, 2.618V	2.6V, 2.618V
13	GND
14	IN / NC	5.2V	5.2V	0	0
15	IN 5.2V / NC
16	IN 5.2V / NC
17	IN / NC	5.2V	5.2V	0	0
18	ADG508 (16)	0	0	5.2V	5.2V
19	ADG508 (1)
20	GND

Local Oscillator

The LO generates two (three) frequencies: 1040MHz (and ??MHz) for the up-converter and 1270MHz for the down-converter

Local Oscillator PCB

Local Oscillator PCB

Description and Block diagram: TODO

Local Oscillator Block Diagram

Flat Cable

W30	LO
Pin	Description
1	15V
2	-15V
3	5.2V
4	GND
5	LO sel 5.2V --> 1040MHz / GND --> ?
6	OUT 0.52V --> LO out of lock (5V OK)
7	GND
8	GND
9	GND
10	GND