Beam Secondary Shower Acquisition System: Cables Measurements

Student MeetingJose Luis Sirvent

PhD. Student22/07/2013

1. Cable measurements campaign.• 1st Experiment layout:

– Frequency Response (Bode Plot ‘Magnitude’)

– Phase displacement (Bode Plot ‘Angle’)

LeCroy Scope

Adapters BNC-N

BNCCh1

50 ohm

Splitter N-2xBNC50 ohm

Loop (double Female)N-Connector

10 ns

10 ns

8 ns

Func. GeneratorBNCCh2

50 ohm

CK502 x 88 m = 176m

1. Cable measurements campaign.• 1st Experiment :

– Frequency Response (Bode Plot ‘Magnitude’)• Measuring the ratio V2rms/V1rms at different frequencies

1. Cable measurements campaign.

Very good agreement Pspice model: Fits well with 176m!!

Analitical functions:Where :C(l), L(l) and Rac(l,f), Gac(l,f)Values of Rac and Gac have been calculated from:http://issues.cern.ch/browse/BIWS-422

1. Cable measurements campaign.• 2nd Experiment layout:

– Pulse distortion (Integrator effect)

– Step response (Low-pass filter)

LeCroy Scope

Adapters SMA-N

SMA-BNCCh1

50 ohm

Splitter SMA-2xSMA

50 ohm

Loop (double Female)N-Connector

4 ns

4 ns

8 ns

Pulse GeneratorSMA-BNC

Ch250 ohm

CK502 x 125 m

1. Cable measurements campaign.• 2nd Experiment (lab testing): Equipment works well, only delay of 8ns

4 ns

4 ns

8 ns

CK 50 Cable Connection

-PicoSecond 2600C:• Pulse generator 1 - 100ns• Selectionable delay• Repetition Rate 1-100KHz• Vo 45V (-70dB) • Zo 50 ohm

-LeCroy Scope:• Sampling Freq 5Gsps• Scale 2ns/div• Zin 50 ohm

-Testing pulses characteristics:• Rise time 419ps• Fall time 837ps• Pulse width700ps• System delay 8ns

1. Cable measurements campaign.• 2nd Experiment (Pulse distortion with Square pulse):

Square pulse ~4ns:

• Rise: 407ps 596ps• Falling: 876ps 3.436ns• Width: 2.464ns 3.298ns

• Whole Pulse: 3.747ns 7.330ns (Δ195%)• Attenuation: 3V 1.75V (-4.68dB)

*Yellow: Input*Pink: Output

1. Cable measurements campaign.• 2nd Experiment (Pulse distortion with ~1.5ns pulse):

Square pulse ~1.5ns:

• Rise: 378ps 606ps• Falling: 860ps 4.375ns• Width: 763ns 1.369ns

• Whole Pulse: 2.001ns 6.350ns (Δ317%)• Attenuation: 2.75V 1V (-8.7dB)

*Yellow: Input*Pink: Output

Beware the long tails!!

25ns

1. Cable measurements campaign.• 2nd Experiment (Step Response & System Identification):

Matlab

System IdentificationToolbox

Arxqs model fits 94.64%!!

Delay = 759ns – 8ns (probe) = 751ns

1. Cable measurements campaign.• Comparison of the Matlab model TF(f)

1. Cable measurements campaign.• Comparison of the Matlab model TF(f)

Matlab model (arxqs)

Pspice model (Tlossy)

1. Cable measurements campaign.• 3rd Experiment layout:

– A) Cable noise measurement (Noise normal distribution & Noise Frequency Spectrum)• Usage of 2 sets of data at different sampling frequency: 500Mhz & 5Ghz

LeCroy Scope

Adapter BNC-N

BNCCh1

50 ohm

Loop (double Female)N-Connector

10 ns

BNCCh2

50 ohm

Load50 ohm

CK502 x 88 m = 176m

1. Cable measurements campaign.• A) Cable noise measurement (Noise Frequency Spectrum Fs= 500Mhz)

• Set 1: 10 Segments of 5ms recorded at 500Mhz with only scope loaded • Set 2: 10 Segments of 5ms recorded at 500Mhz with cable loaded• Extraction of FFT 1 – 250Mhz for each segment measured in set 1 and averages of FFT• Extraction of FFT 1 – 250Mhz for each segment measured in set 2 and averages of FFT

FM Radio Stations& TV

AM Radio Stations& Others

A

B

1. Cable measurements campaign.• A) Cable noise measurement (Noise Frequency Spectrum Fs= 5Ghz)

• Set 1: 10 Segments of 500us recorded at 5Ghz with only scope loaded • Set 2: 10 Segments of 500us recorded at 5Ghz with cable loaded• Extraction of FFT 1 – 2.5Ghz for each segment measured in set 1 and averages of FFT• Extraction of FFT 1 – 2.5Ghz for each segment measured in set 2 and averages of FFT

TV Stations GSM-900 GSM-1800WI-FI

C

D

1. Cable measurements campaign.• A) Cable noise measurement (Noise Frequency Spectrum Fs= 500Mhz & 5Ghz )

• A look in detail (Most important contribution 330KHz!!)

300KHz

1.67GHz750MHz

167MHzA B

C D

1. Cable measurements campaign.• A) Cable noise measurement (Noise Frequency Spectrum Fs= 500Mhz & 5Ghz )

• A look in semi-logaritmic scale (Easier to see that the most important contribution is at 330KHz!!)

1. Cable measurements campaign.• A) Cable noise measurement (Noise Frequency Spectrum Fs= 500Mhz)

1.23Khz

19.6Khz

330Khz

1. Cable measurements campaign.• A) Cable noise measurement (Amplitude distribution at Fs= 500Mhz)

1. Cable measurements campaign.• A) Cable noise measurement (Amplitude distribution at Fs= 5Ghz)