User's Manual
8
Part Number: J24004
Drawing Control: JD16049
POWER CONTROL AND INTERMODULATION
Power control circuitry is provided to prevent excess output power and, thus, excess 3rd order intermodulation
distortion (IMD). IMD levels are a function of the output power and the IP3 of the amplifier stages [IM = 3(Po) -
2(IP3)]. The FCC regulations specify the maximum IMD levels at -13 dBm. Each BDA is tested and set for
maximum IMD levels of -13 dBm in either RF link. The resultant power setting is the "Usable Output Power" in
the general specifications. However, the typical IMD for PCS 1900 is below -30 dBm.
The Power control circuitry senses output power. If the output power attempts to exceed the factory setting,
generally due to strong input signals, the Power control circuitry introduces gain attenuation, maintaining output
power to the preset limit [Pin + Gain - Attenuation = Pout]. When the input signal is too strong, the attenuation
range of the Power Control circuitry is exceeded; the output power will increase beyond the factory setting. In this
situation, it is likely that IMD levels will exceed -13 dBm. If this is expected to be a consistent problem, some input
attenuation should be provided.
The yellow LEDs, "UL PWR and DL PWR", on the front panel will light up whenever the Power Control circuitry
is active. The advantage of using Power control circuitry stage is two-fold. First, the dynamic range of the
amplifier is increased. A wider range of input signal levels can be handled by the system. This advantage can also
be stated in terms of gain. More gain can be put into the system to handle weak signals without risking premature
compression and excessive intermodulation emissions due to stronger signals. The second significant advantage is
that intermodulation products are kept to acceptable levels. As more channels become active, or as some signals
become stronger, gain is reduced and total output power is kept constant.
REMOTE INTERFACE
TYPE OF SERVICE:
The intelliBDA is designed to be used on standard device telephone lines connected to the telephone line by means
of a standard jack called the USOC RJ-11C (or USOC FJ45S). Connection to telephone company provided coin
service (central office implemented systems) is prohibited. Connection to party lines service subject to state tariffs.
TELEPHONE COMPANY PROCEDURES:
The goal of the telephone company is to provide you with the best service it can. In order to do this; it may
occasionally be necessary for them to make changes in their equipment, operations or procedures. These changes
might affect your service or the operation of your equipment, the telephone company will give you notice, in writing,
to allow you to make any changes necessary to maintain uninterrupted service.
In certain circumstances, it may be necessary for the telephone company to request information from you concerning
the equipment, which you have connected to your telephone line. Upon request of the telephone company, provide
the FCC registration number and the ringer equivalence number (REN); both of these items are listed on the
equipment label. The sum of all of the RENs on your telephone lines should be less than five in order to assure
proper service from the telephone company. In some cases, a sum of five may not be usable on a given line.
IF PROBLEM ARISE:
If any of your telephone equipment is not operating properly, you should immediately remove it from your telephone
line, as it may cause harm to the telephone network. If the telephone company notes a problem, they may temporarily