MCP3909-I/SS Microchip Technology, MCP3909-I/SS Datasheet - Page 76

• Manufacturer Part Number: MCP3909-I/SS
• Description: IC POWER METERING-1 PHASE 24SSOP
• Manufacturer: Microchip Technology

Specifications of MCP3909-I/SS

• Package / Case: 24-SSOP (0.200", 5.30mm Width)
• Input Impedance: 390 KOhm
• Measurement Error: 0.1%
• Voltage - I/o High: 2.4V
• Voltage - I/o Low: 0.85V
• Current - Supply: 2.3mA
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Meter Type: Single Phase
• Operating Temperature Range: - 40 C to + 85 C
• Mounting Style: SMD/SMT
• Supply Voltage Range: 4.5V To 5.5V
• Digital Ic Case Style: SSOP
• No. Of Pins: 24
• Interface Type: Serial, SPI
• Supply Voltage Max: 5.5V
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: MCP3909EV-MCU16 - EVALUATION BOARD FOR MCP3909MCP3909RD-3PH1 - REF DESIGN MCP3909 3PH ENGY MTR
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design
DS51723A-page 76
FIGURE C-1:
C.2.1
Assuming that the average of a periodic signal in one cycle is g(t),
EQUATION C-1:
Make t = x/
EQUATION C-2:
where f(x) = g(x/
If the entire period sampling cannot be realized while a sampling frequency deviation
Δ exists, then:
EQUATION C-3:
We have:
EQUATION C-4:
The value of F
non--synchronous sampling error E = f(x)- F
As F
within the range of 0-2
1
(α) is function with 2
Basic Idea of Quasi-Synchronous Sampling
ω
, then,
1
(α) is a function of
ω
), and the period is 2π.
f x ( )
Quasi Synchronous Sampline.
π
≠
, and it can be deduced that f(x) = F
---------------- -
2
π
π
g t ( )
1
V
+
as its period, its value may be averaged through integration
F
Δ
1
⋅
( )
=
g t ( )
α
(
2
π
-- -
T
1
∫
0
=
+
α
Ts
⋅
=
T
∫
0
Δ
---------------- -
2
T≠N*Ts
g
and also a function with 2π as its perod. The
)
----- -
2
π
t ( )dt
f x ( ) x
1
π
1
+
⋅
d
Δ
2
∫
0
π
⋅
=
≠
f x ( ) x d
(
1
α
---------------- -
2
(α).
1
-- -
T
π
+
1
⋅
+
2
α
∫
(
π
TO
Δ
=
+
TO
⋅
∫
Δ
+
(
f x ( )
α
)
T
f x ( ) x d
)
+
g
2
t ( )dt
α
∫
π
+
© 2009 Microchip Technology Inc.
Δ
t
1
)
(α).
f x ( ) x
d